diff --git a/PSI-MOD-newstyle.obo b/PSI-MOD-newstyle.obo
index a05e132..b9fc6db 100644
--- a/PSI-MOD-newstyle.obo
+++ b/PSI-MOD-newstyle.obo
@@ -1,7 +1,7 @@
 format-version: 1.2
 ontology: mod
-date: 13:06:2021 12:12
-saved-by: Charles Tapley Hoyt
+date: 17:11:2025 12:12
+saved-by: Eric Deutsch
 subsetdef: PSI-MOD-slim "subset of protein modifications"
 synonymtypedef: DeltaMass-label "Label from MS DeltaMass" EXACT
 synonymtypedef: OMSSA-label "Short label from OMSSA" EXACT
@@ -17,8 +17,8 @@ synonymtypedef: Unimod-description "Description (full_name) from Unimod" RELATED
 synonymtypedef: Unimod-interim "Interim label from Unimod" RELATED
 synonymtypedef: UniProt-feature "Protein feature description from UniProtKB" EXACT
 default-namespace: PSI-MOD
-data-version: 1.031.5
-remark: PSI-MOD version: 1.031.5
+data-version: 1.032.4
+remark: PSI-MOD version: 1.032.4
 remark: RESID release: 75.00
 remark: ISO-8601 date: 2022-06-13 12:12Z
 remark: Annotation note 01 - \"[PSI-MOD:ref]\" has been replaced by PubMed:18688235.
@@ -46,7 +46,7 @@ name: alkylated residue
 def: "A protein modification that effectively replaces a hydrogen atom with an alkyl group." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "AlkylRes" EXACT PSI-MOD-label []
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:00002
@@ -56,15 +56,15 @@ subset: PSI-MOD-slim
 synonym: "OGlycoSer" EXACT PSI-MOD-label []
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00396
-is_a: MOD:00916
+is_a: MOD:00396 ! O-glycosylated residue
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:00003
 name: Unimod
 def: "Entry from Unimod." [PubMed:18688235]
 comment: This term is for organizational use only and should not be assigned. [JSG]
-is_a: MOD:00032
+is_a: MOD:00032 ! uncategorized protein modification
 
 [Term]
 id: MOD:00004
@@ -80,8 +80,8 @@ subset: PSI-MOD-slim
 synonym: "OGlycoThr" EXACT PSI-MOD-label []
 property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00396
-is_a: MOD:00917
+is_a: MOD:00396 ! O-glycosylated residue
+is_a: MOD:00917 ! modified L-threonine residue
 
 [Term]
 id: MOD:00006
@@ -89,7 +89,7 @@ name: N-glycosylated residue
 def: "A protein modification that effectively replaces a residue hydrogen atom on a nitrogen with a carbohydrate-like group through a glycosidic bond." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "NGlycoRes" EXACT PSI-MOD-label []
-is_a: MOD:00693
+is_a: MOD:00693 ! glycosylated residue
 
 [Term]
 id: MOD:00007
@@ -104,7 +104,7 @@ property_value: DiffMono "47.944450" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:162
-is_a: MOD:00745
+is_a: MOD:00745 ! selenium containing residue
 
 [Term]
 id: MOD:00008
@@ -121,7 +121,7 @@ synonym: "alpha-amino acid" EXACT RESID-name []
 synonym: "Res" EXACT PSI-MOD-label []
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:01157
+is_a: MOD:01157 ! protein modification categorized by amino acid modified
 
 [Term]
 id: MOD:00010
@@ -143,9 +143,9 @@ property_value: MassAvg "71.08" xsd:float
 property_value: MassMono "71.037114" xsd:float
 property_value: Origin "A" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00570
-is_a: MOD:00859
-is_a: MOD:01441
+is_a: MOD:00570 ! residues isobaric at 71.037114 Da
+is_a: MOD:00859 ! modified residue that can arise from different natural residues
+is_a: MOD:01441 ! natural, standard, encoded residue
 
 [Term]
 id: MOD:00011
@@ -169,7 +169,7 @@ property_value: MassAvg "156.19" xsd:float
 property_value: MassMono "156.101111" xsd:float
 property_value: Origin "R" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:01441
+is_a: MOD:01441 ! natural, standard, encoded residue
 
 [Term]
 id: MOD:00012
@@ -198,8 +198,8 @@ property_value: MassAvg "114.10" xsd:float
 property_value: MassMono "114.042927" xsd:float
 property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00859
-is_a: MOD:01441
+is_a: MOD:00859 ! modified residue that can arise from different natural residues
+is_a: MOD:01441 ! natural, standard, encoded residue
 
 [Term]
 id: MOD:00013
@@ -219,8 +219,8 @@ property_value: MassAvg "115.09" xsd:float
 property_value: MassMono "115.026943" xsd:float
 property_value: Origin "D" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00859
-is_a: MOD:01441
+is_a: MOD:00859 ! modified residue that can arise from different natural residues
+is_a: MOD:01441 ! natural, standard, encoded residue
 
 [Term]
 id: MOD:00014
@@ -252,8 +252,8 @@ property_value: MassAvg "103.14" xsd:float
 property_value: MassMono "103.009185" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00859
-is_a: MOD:01441
+is_a: MOD:00859 ! modified residue that can arise from different natural residues
+is_a: MOD:01441 ! natural, standard, encoded residue
 
 [Term]
 id: MOD:00015
@@ -276,8 +276,8 @@ property_value: MassAvg "129.12" xsd:float
 property_value: MassMono "129.042593" xsd:float
 property_value: Origin "E" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00859
-is_a: MOD:01441
+is_a: MOD:00859 ! modified residue that can arise from different natural residues
+is_a: MOD:01441 ! natural, standard, encoded residue
 
 [Term]
 id: MOD:00016
@@ -303,8 +303,8 @@ property_value: MassAvg "128.13" xsd:float
 property_value: MassMono "128.058578" xsd:float
 property_value: Origin "Q" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00894
-is_a: MOD:01441
+is_a: MOD:00894 ! residues isobaric at 128.058578 Da
+is_a: MOD:01441 ! natural, standard, encoded residue
 
 [Term]
 id: MOD:00017
@@ -325,7 +325,7 @@ property_value: MassAvg "57.05" xsd:float
 property_value: MassMono "57.021464" xsd:float
 property_value: Origin "G" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:01441
+is_a: MOD:01441 ! natural, standard, encoded residue
 
 [Term]
 id: MOD:00018
@@ -349,7 +349,7 @@ property_value: MassAvg "137.14" xsd:float
 property_value: MassMono "137.058912" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:01441
+is_a: MOD:01441 ! natural, standard, encoded residue
 
 [Term]
 id: MOD:00019
@@ -372,8 +372,8 @@ property_value: MassAvg "113.16" xsd:float
 property_value: MassMono "113.084064" xsd:float
 property_value: Origin "I" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00306
-is_a: MOD:01441
+is_a: MOD:00306 ! residues isobaric at 113.084064 Da
+is_a: MOD:01441 ! natural, standard, encoded residue
 
 [Term]
 id: MOD:00020
@@ -395,8 +395,8 @@ property_value: MassAvg "113.16" xsd:float
 property_value: MassMono "113.084064" xsd:float
 property_value: Origin "L" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00306
-is_a: MOD:01441
+is_a: MOD:00306 ! residues isobaric at 113.084064 Da
+is_a: MOD:01441 ! natural, standard, encoded residue
 
 [Term]
 id: MOD:00021
@@ -418,8 +418,8 @@ property_value: MassAvg "128.18" xsd:float
 property_value: MassMono "128.094963" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00893
-is_a: MOD:01441
+is_a: MOD:00893 ! residues isobaric at 128.0-128.1
+is_a: MOD:01441 ! natural, standard, encoded residue
 
 [Term]
 id: MOD:00022
@@ -446,7 +446,7 @@ property_value: MassAvg "131.19" xsd:float
 property_value: MassMono "131.040485" xsd:float
 property_value: Origin "M" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:01441
+is_a: MOD:01441 ! natural, standard, encoded residue
 
 [Term]
 id: MOD:00023
@@ -466,7 +466,7 @@ property_value: MassAvg "147.18" xsd:float
 property_value: MassMono "147.068414" xsd:float
 property_value: Origin "F" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:01441
+is_a: MOD:01441 ! natural, standard, encoded residue
 
 [Term]
 id: MOD:00024
@@ -485,7 +485,7 @@ property_value: MassAvg "97.12" xsd:float
 property_value: MassMono "97.052764" xsd:float
 property_value: Origin "P" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:01441
+is_a: MOD:01441 ! natural, standard, encoded residue
 
 [Term]
 id: MOD:00025
@@ -507,7 +507,7 @@ property_value: MassAvg "87.08" xsd:float
 property_value: MassMono "87.032028" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:01441
+is_a: MOD:01441 ! natural, standard, encoded residue
 
 [Term]
 id: MOD:00026
@@ -529,7 +529,7 @@ property_value: MassAvg "101.10" xsd:float
 property_value: MassMono "101.047678" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:01441
+is_a: MOD:01441 ! natural, standard, encoded residue
 
 [Term]
 id: MOD:00027
@@ -550,7 +550,7 @@ property_value: MassAvg "186.21" xsd:float
 property_value: MassMono "186.079313" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:01441
+is_a: MOD:01441 ! natural, standard, encoded residue
 
 [Term]
 id: MOD:00028
@@ -572,7 +572,7 @@ property_value: MassAvg "163.18" xsd:float
 property_value: MassMono "163.063329" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:01441
+is_a: MOD:01441 ! natural, standard, encoded residue
 
 [Term]
 id: MOD:00029
@@ -593,7 +593,7 @@ property_value: MassAvg "99.13" xsd:float
 property_value: MassMono "99.068414" xsd:float
 property_value: Origin "V" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:01441
+is_a: MOD:01441 ! natural, standard, encoded residue
 
 [Term]
 id: MOD:00030
@@ -619,7 +619,7 @@ property_value: MassMono "160.043225" xsd:float
 property_value: Origin "M" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00868
+is_a: MOD:00868 ! natural, non-standard encoded residue
 
 [Term]
 id: MOD:00031
@@ -642,16 +642,16 @@ property_value: MassAvg "150.05" xsd:float
 property_value: MassMono "150.953635" xsd:float
 property_value: Origin "U" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00745
-is_a: MOD:00859
-is_a: MOD:00868
+is_a: MOD:00745 ! selenium containing residue
+is_a: MOD:00859 ! modified residue that can arise from different natural residues
+is_a: MOD:00868 ! natural, non-standard encoded residue
 
 [Term]
 id: MOD:00032
 name: uncategorized protein modification
 def: "A protein modification that is not chemically categorized." [PubMed:18688235]
 comment: This term is for organizational use only and should not be assigned. [JSG]
-is_a: MOD:00000
+is_a: MOD:00000 ! protein modification
 
 [Term]
 id: MOD:00033
@@ -660,7 +660,7 @@ def: "A protein modification that crosslinks two or more amino acid residues wit
 comment: The covalent bond is formed directly between sidechain atoms. If non-aminoacid atoms are involved in connecting two or more peptide chain residues peptide chain, the connection is classified as a multivalent binding site.
 subset: PSI-MOD-slim
 synonym: "XLNK-Res-Res" EXACT PSI-MOD-label []
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:00034
@@ -693,7 +693,7 @@ property_value: MassAvg "204.26" xsd:float
 property_value: MassMono "204.002720" xsd:float
 property_value: Origin "C, C" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00689
+is_a: MOD:00689 ! disulfide crosslinked residues
 
 [Term]
 id: MOD:00035
@@ -717,7 +717,7 @@ property_value: MassMono "130.037842" xsd:float
 property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0369
-is_a: MOD:01688
+is_a: MOD:01688 ! 3-hydroxy-L-asparagine
 
 [Term]
 id: MOD:00036
@@ -745,7 +745,7 @@ property_value: Origin "D" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:35
 xref: uniprot.ptm:PTM-0371
-is_a: MOD:01926
+is_a: MOD:01926 ! 3-hydroxy-L-aspartic acid
 
 [Term]
 id: MOD:00037
@@ -763,7 +763,7 @@ property_value: MassMono "144.089878" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0044
-is_a: MOD:01047
+is_a: MOD:01047 ! monohydroxylated lysine
 
 [Term]
 id: MOD:00038
@@ -787,7 +787,7 @@ property_value: MassMono "113.047678" xsd:float
 property_value: Origin "P" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0030
-is_a: MOD:01024
+is_a: MOD:01024 ! monohydroxylated proline
 
 [Term]
 id: MOD:00039
@@ -812,7 +812,7 @@ property_value: MassMono "113.047678" xsd:float
 property_value: Origin "P" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0043
-is_a: MOD:01024
+is_a: MOD:01024 ! monohydroxylated proline
 
 [Term]
 id: MOD:00040
@@ -847,9 +847,9 @@ property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:28
 xref: uniprot.ptm:PTM-0261
-is_a: MOD:00907
-is_a: MOD:01048
-is_a: MOD:01160
+is_a: MOD:00907 ! modified L-glutamine residue
+is_a: MOD:01048 ! 2-pyrrolidone-5-carboxylic acid
+is_a: MOD:01160 ! deaminated residue
 
 [Term]
 id: MOD:00041
@@ -882,8 +882,8 @@ property_value: Origin "E" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:299
 xref: uniprot.ptm:PTM-0039
-is_a: MOD:00906
-is_a: MOD:01152
+is_a: MOD:00906 ! modified L-glutamic acid residue
+is_a: MOD:01152 ! carboxylated residue
 
 [Term]
 id: MOD:00042
@@ -912,8 +912,8 @@ property_value: Origin "D" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:21
 xref: uniprot.ptm:PTM-0038
-is_a: MOD:00904
-is_a: MOD:01455
+is_a: MOD:00904 ! modified L-aspartic acid residue
+is_a: MOD:01455 ! O-phosphorylated residue
 
 [Term]
 id: MOD:00043
@@ -941,9 +941,9 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:21
 xref: uniprot.ptm:PTM-0251
-is_a: MOD:00696
-is_a: MOD:00777
-is_a: MOD:00905
+is_a: MOD:00696 ! phosphorylated residue
+is_a: MOD:00777 ! residues isobaric at 182.96-182.98 Da
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00044
@@ -975,7 +975,7 @@ property_value: MassMono "217.025242" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0325
-is_a: MOD:00890
+is_a: MOD:00890 ! phosphorylated L-histidine
 
 [Term]
 id: MOD:00045
@@ -1007,7 +1007,7 @@ property_value: MassMono "217.025242" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0260
-is_a: MOD:00890
+is_a: MOD:00890 ! phosphorylated L-histidine
 
 [Term]
 id: MOD:00046
@@ -1039,9 +1039,9 @@ property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:21
 xref: uniprot.ptm:PTM-0253
-is_a: MOD:00771
-is_a: MOD:00916
-is_a: MOD:01455
+is_a: MOD:00771 ! residues isobaric at 166.98-167.00 Da
+is_a: MOD:00916 ! modified L-serine residue
+is_a: MOD:01455 ! O-phosphorylated residue
 
 [Term]
 id: MOD:00047
@@ -1071,9 +1071,9 @@ property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:21
 xref: uniprot.ptm:PTM-0254
-is_a: MOD:00773
-is_a: MOD:00917
-is_a: MOD:01455
+is_a: MOD:00773 ! residues isobaric at 181.00-181.02 Da
+is_a: MOD:00917 ! modified L-threonine residue
+is_a: MOD:01455 ! O-phosphorylated residue
 
 [Term]
 id: MOD:00048
@@ -1103,9 +1103,9 @@ property_value: Origin "Y" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:21
 xref: uniprot.ptm:PTM-0255
-is_a: MOD:00774
-is_a: MOD:00919
-is_a: MOD:01455
+is_a: MOD:00774 ! residues isobaric at 243.02-243.03 Da
+is_a: MOD:00919 ! modified L-tyrosine residue
+is_a: MOD:01455 ! O-phosphorylated residue
 
 [Term]
 id: MOD:00049
@@ -1137,7 +1137,7 @@ property_value: Origin "H" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:375
 xref: uniprot.ptm:PTM-0118
-is_a: MOD:00909
+is_a: MOD:00909 ! modified L-histidine residue
 
 [Term]
 id: MOD:00050
@@ -1162,8 +1162,8 @@ property_value: Origin "A" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0199
-is_a: MOD:00901
-is_a: MOD:01458
+is_a: MOD:00901 ! modified L-alanine residue
+is_a: MOD:01458 ! alpha-amino acetylated residue
 
 [Term]
 id: MOD:00051
@@ -1188,8 +1188,8 @@ property_value: Origin "D" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0200
-is_a: MOD:00904
-is_a: MOD:01458
+is_a: MOD:00904 ! modified L-aspartic acid residue
+is_a: MOD:01458 ! alpha-amino acetylated residue
 
 [Term]
 id: MOD:00052
@@ -1217,8 +1217,8 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0201
-is_a: MOD:00646
-is_a: MOD:01458
+is_a: MOD:00646 ! acetylated L-cysteine
+is_a: MOD:01458 ! alpha-amino acetylated residue
 
 [Term]
 id: MOD:00053
@@ -1243,8 +1243,8 @@ property_value: Origin "E" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0202
-is_a: MOD:00906
-is_a: MOD:01458
+is_a: MOD:00906 ! modified L-glutamic acid residue
+is_a: MOD:01458 ! alpha-amino acetylated residue
 
 [Term]
 id: MOD:00054
@@ -1268,8 +1268,8 @@ property_value: MassMono "171.076967" xsd:float
 property_value: Origin "Q" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00907
-is_a: MOD:01458
+is_a: MOD:00907 ! modified L-glutamine residue
+is_a: MOD:01458 ! alpha-amino acetylated residue
 
 [Term]
 id: MOD:00055
@@ -1295,8 +1295,8 @@ property_value: Origin "G" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0203
-is_a: MOD:00908
-is_a: MOD:01458
+is_a: MOD:00908 ! modified glycine residue
+is_a: MOD:01458 ! alpha-amino acetylated residue
 
 [Term]
 id: MOD:00056
@@ -1320,8 +1320,8 @@ property_value: Origin "I" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0204
-is_a: MOD:00910
-is_a: MOD:01458
+is_a: MOD:00910 ! modified L-isoleucine residue
+is_a: MOD:01458 ! alpha-amino acetylated residue
 
 [Term]
 id: MOD:00057
@@ -1345,8 +1345,8 @@ property_value: MassMono "171.113353" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00723
-is_a: MOD:01458
+is_a: MOD:00723 ! N-acetylated L-lysine
+is_a: MOD:01458 ! alpha-amino acetylated residue
 
 [Term]
 id: MOD:00058
@@ -1373,8 +1373,8 @@ property_value: Origin "M" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0205
-is_a: MOD:00913
-is_a: MOD:01458
+is_a: MOD:00913 ! modified L-methionine residue
+is_a: MOD:01458 ! alpha-amino acetylated residue
 
 [Term]
 id: MOD:00059
@@ -1399,8 +1399,8 @@ property_value: Origin "P" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0206
-is_a: MOD:00915
-is_a: MOD:01458
+is_a: MOD:00915 ! modified L-proline residue
+is_a: MOD:01458 ! alpha-amino acetylated residue
 
 [Term]
 id: MOD:00060
@@ -1426,8 +1426,8 @@ property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0207
-is_a: MOD:00647
-is_a: MOD:01458
+is_a: MOD:00647 ! acetylated L-serine
+is_a: MOD:01458 ! alpha-amino acetylated residue
 
 [Term]
 id: MOD:00061
@@ -1455,8 +1455,8 @@ property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0208
-is_a: MOD:01186
-is_a: MOD:01458
+is_a: MOD:01186 ! acetylated L-threonine
+is_a: MOD:01458 ! alpha-amino acetylated residue
 
 [Term]
 id: MOD:00062
@@ -1481,8 +1481,8 @@ property_value: Origin "Y" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0209
-is_a: MOD:00919
-is_a: MOD:01458
+is_a: MOD:00919 ! modified L-tyrosine residue
+is_a: MOD:01458 ! alpha-amino acetylated residue
 
 [Term]
 id: MOD:00063
@@ -1507,8 +1507,8 @@ property_value: Origin "V" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0210
-is_a: MOD:00920
-is_a: MOD:01458
+is_a: MOD:00920 ! modified L-valine residue
+is_a: MOD:01458 ! alpha-amino acetylated residue
 
 [Term]
 id: MOD:00064
@@ -1537,8 +1537,8 @@ property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:1
 xref: uniprot.ptm:PTM-0190
-is_a: MOD:00723
-is_a: MOD:01875
+is_a: MOD:00723 ! N-acetylated L-lysine
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:00065
@@ -1564,8 +1564,8 @@ property_value: MassMono "145.019749" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:1
-is_a: MOD:00645
-is_a: MOD:00646
+is_a: MOD:00645 ! mono S-acetylated residue
+is_a: MOD:00646 ! monoacetylated L-cysteine
 
 [Term]
 id: MOD:00066
@@ -1591,9 +1591,9 @@ property_value: Origin "G" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0211
-is_a: MOD:00409
-is_a: MOD:00908
-is_a: MOD:01696
+is_a: MOD:00409 ! N-formylated residue
+is_a: MOD:00908 ! modified glycine residue
+is_a: MOD:01696 ! alpha-amino acylated residue
 
 [Term]
 id: MOD:00067
@@ -1616,8 +1616,8 @@ property_value: Origin "G" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0331
-is_a: MOD:00447
-is_a: MOD:00908
+is_a: MOD:00447 ! N-glucuronylated residue
+is_a: MOD:00908 ! modified glycine residue
 
 [Term]
 id: MOD:00068
@@ -1647,9 +1647,9 @@ property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:45
 xref: uniprot.ptm:PTM-0221
-is_a: MOD:00650
-is_a: MOD:00908
-is_a: MOD:01696
+is_a: MOD:00650 ! N-myristoylated residue
+is_a: MOD:00908 ! modified glycine residue
+is_a: MOD:01696 ! alpha-amino acylated residue
 
 [Term]
 id: MOD:00069
@@ -1678,8 +1678,8 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0222
-is_a: MOD:01684
-is_a: MOD:01685
+is_a: MOD:01684 ! palmitoylated-L-cysteine
+is_a: MOD:01685 ! alpha-amino palmitoylated residue
 
 [Term]
 id: MOD:00070
@@ -1706,8 +1706,8 @@ property_value: Origin "A" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0214
-is_a: MOD:01461
-is_a: MOD:01680
+is_a: MOD:01461 ! N-methylated alanine
+is_a: MOD:01680 ! alpha-amino monomethylated residue
 
 [Term]
 id: MOD:00071
@@ -1737,8 +1737,8 @@ property_value: Origin "A" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0177
-is_a: MOD:01461
-is_a: MOD:01698
+is_a: MOD:01461 ! N-methylated alanine
+is_a: MOD:01698 ! alpha-amino trimethylated protonated-residue
 
 [Term]
 id: MOD:00072
@@ -1767,9 +1767,9 @@ property_value: Origin "G" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0483
-is_a: MOD:00570
-is_a: MOD:00714
-is_a: MOD:01680
+is_a: MOD:00570 ! residues isobaric at 71.037114 Da
+is_a: MOD:00714 ! methylated glycine
+is_a: MOD:01680 ! alpha-amino monomethylated residue
 
 [Term]
 id: MOD:00073
@@ -1797,8 +1797,8 @@ property_value: Origin "M" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0217
-is_a: MOD:01463
-is_a: MOD:01680
+is_a: MOD:01463 ! N-methylated methionine
+is_a: MOD:01680 ! alpha-amino monomethylated residue
 
 [Term]
 id: MOD:00074
@@ -1824,8 +1824,8 @@ property_value: Origin "F" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0218
-is_a: MOD:01063
-is_a: MOD:01680
+is_a: MOD:01063 ! monomethylated phenylalanine
+is_a: MOD:01680 ! alpha-amino monomethylated residue
 
 [Term]
 id: MOD:00075
@@ -1856,8 +1856,8 @@ property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:529
 xref: uniprot.ptm:PTM-0179
-is_a: MOD:00710
-is_a: MOD:01462
+is_a: MOD:00710 ! protonated-dimethylated residue
+is_a: MOD:01462 ! N-methylated proline
 
 [Term]
 id: MOD:00076
@@ -1886,8 +1886,8 @@ property_value: Origin "R" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:36
 xref: uniprot.ptm:PTM-0287
-is_a: MOD:00602
-is_a: MOD:00783
+is_a: MOD:00602 ! N-methylated residue
+is_a: MOD:00783 ! dimethylated L-arginine
 
 [Term]
 id: MOD:00077
@@ -1915,8 +1915,8 @@ property_value: Origin "R" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:36
 xref: uniprot.ptm:PTM-0066
-is_a: MOD:00602
-is_a: MOD:00783
+is_a: MOD:00602 ! N-methylated residue
+is_a: MOD:00783 ! dimethylated L-arginine
 
 [Term]
 id: MOD:00078
@@ -1941,8 +1941,8 @@ property_value: MassMono "170.116761" xsd:float
 property_value: Origin "R" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0237
-is_a: MOD:00414
-is_a: MOD:00602
+is_a: MOD:00414 ! monomethylated L-arginine
+is_a: MOD:00602 ! N-methylated residue
 
 [Term]
 id: MOD:00079
@@ -1971,10 +1971,10 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:34
 xref: uniprot.ptm:PTM-0183
-is_a: MOD:00599
-is_a: MOD:00602
-is_a: MOD:00673
-is_a: MOD:00894
+is_a: MOD:00599 ! monomethylated residue
+is_a: MOD:00602 ! N-methylated residue
+is_a: MOD:00673 ! methylated asparagine
+is_a: MOD:00894 ! residues isobaric at 128.058578 Da
 
 [Term]
 id: MOD:00080
@@ -2001,8 +2001,8 @@ property_value: MassMono "142.074228" xsd:float
 property_value: Origin "Q" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0185
-is_a: MOD:00602
-is_a: MOD:00722
+is_a: MOD:00602 ! N-methylated residue
+is_a: MOD:00722 ! monomethylated L-glutamine
 
 [Term]
 id: MOD:00081
@@ -2037,7 +2037,7 @@ property_value: Origin "E" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:34
 xref: uniprot.ptm:PTM-0128
-is_a: MOD:01453
+is_a: MOD:01453 ! L-glutamic acid 5-methyl ester
 
 [Term]
 id: MOD:00082
@@ -2064,8 +2064,8 @@ property_value: MassMono "151.074562" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0259
-is_a: MOD:02038
-is_a: MOD:00724
+is_a: MOD:02038 ! monomethylated L-histidine
+is_a: MOD:00724 ! N-methylated L-histidine
 
 [Term]
 id: MOD:00083
@@ -2097,9 +2097,9 @@ property_value: MassMono "171.149190" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0187
-is_a: MOD:00602
-is_a: MOD:00663
-is_a: MOD:00711
+is_a: MOD:00602 ! N-methylated residue
+is_a: MOD:00663 ! methylated lysine
+is_a: MOD:00711 ! trimethylated protonated-residue
 
 [Term]
 id: MOD:00084
@@ -2127,9 +2127,9 @@ property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:36
 xref: uniprot.ptm:PTM-0188
-is_a: MOD:00429
-is_a: MOD:00602
-is_a: MOD:00663
+is_a: MOD:00429 ! dimethylated residue
+is_a: MOD:00602 ! N-methylated residue
+is_a: MOD:00663 ! methylated lysine
 
 [Term]
 id: MOD:00085
@@ -2156,8 +2156,8 @@ property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:34
 xref: uniprot.ptm:PTM-0194
-is_a: MOD:00602
-is_a: MOD:01683
+is_a: MOD:00602 ! N-methylated residue
+is_a: MOD:01683 ! monomethylated L-lysine
 
 [Term]
 id: MOD:00086
@@ -2187,8 +2187,8 @@ property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:47
 xref: uniprot.ptm:PTM-0197
-is_a: MOD:00651
-is_a: MOD:01875
+is_a: MOD:00651 ! N-palmitoylated residue
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:00087
@@ -2218,8 +2218,8 @@ property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:45
 xref: uniprot.ptm:PTM-0196
-is_a: MOD:00650
-is_a: MOD:01875
+is_a: MOD:00650 ! N-myristoylated residue
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:00088
@@ -2248,8 +2248,8 @@ property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:47
 xref: uniprot.ptm:PTM-0242
-is_a: MOD:00652
-is_a: MOD:02004
+is_a: MOD:00652 ! O-palmitoylated residue
+is_a: MOD:02004 ! O3-acylated L-threonine
 
 [Term]
 id: MOD:00089
@@ -2279,8 +2279,8 @@ property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:47
 xref: uniprot.ptm:PTM-0241
-is_a: MOD:00652
-is_a: MOD:02003
+is_a: MOD:00652 ! O-palmitoylated residue
+is_a: MOD:02003 ! O3-acylated L-serine
 
 [Term]
 id: MOD:00090
@@ -2303,8 +2303,8 @@ property_value: Origin "A" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0057
-is_a: MOD:00883
-is_a: MOD:00901
+is_a: MOD:00883 ! C1-amidated residue
+is_a: MOD:00901 ! modified L-alanine residue
 
 [Term]
 id: MOD:00091
@@ -2329,8 +2329,8 @@ property_value: Origin "R" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0060
-is_a: MOD:00883
-is_a: MOD:00902
+is_a: MOD:00883 ! C1-amidated residue
+is_a: MOD:00902 ! modified L-arginine residue
 
 [Term]
 id: MOD:00092
@@ -2353,8 +2353,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0062
-is_a: MOD:00883
-is_a: MOD:00903
+is_a: MOD:00883 ! C1-amidated residue
+is_a: MOD:00903 ! modified L-asparagine residue
 
 [Term]
 id: MOD:00093
@@ -2380,8 +2380,8 @@ property_value: Origin "D" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0063
-is_a: MOD:00883
-is_a: MOD:00904
+is_a: MOD:00883 ! C1-amidated residue
+is_a: MOD:00904 ! modified L-aspartic acid residue
 
 [Term]
 id: MOD:00094
@@ -2405,8 +2405,8 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0102
-is_a: MOD:00883
-is_a: MOD:00905
+is_a: MOD:00883 ! C1-amidated residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00095
@@ -2429,8 +2429,8 @@ property_value: Origin "Q" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0130
-is_a: MOD:00883
-is_a: MOD:00907
+is_a: MOD:00883 ! C1-amidated residue
+is_a: MOD:00907 ! modified L-glutamine residue
 
 [Term]
 id: MOD:00096
@@ -2454,8 +2454,8 @@ property_value: Origin "E" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0129
-is_a: MOD:00883
-is_a: MOD:00906
+is_a: MOD:00883 ! C1-amidated residue
+is_a: MOD:00906 ! modified L-glutamic acid residue
 
 [Term]
 id: MOD:00097
@@ -2480,8 +2480,8 @@ property_value: Origin "G" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0132
-is_a: MOD:00883
-is_a: MOD:00908
+is_a: MOD:00883 ! C1-amidated residue
+is_a: MOD:00908 ! modified glycine residue
 
 [Term]
 id: MOD:00098
@@ -2504,8 +2504,8 @@ property_value: Origin "H" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0148
-is_a: MOD:00883
-is_a: MOD:00909
+is_a: MOD:00883 ! C1-amidated residue
+is_a: MOD:00909 ! modified L-histidine residue
 
 [Term]
 id: MOD:00099
@@ -2528,8 +2528,8 @@ property_value: Origin "I" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0161
-is_a: MOD:00883
-is_a: MOD:00910
+is_a: MOD:00883 ! C1-amidated residue
+is_a: MOD:00910 ! modified L-isoleucine residue
 
 [Term]
 id: MOD:00100
@@ -2555,8 +2555,8 @@ property_value: Origin "L" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0166
-is_a: MOD:00883
-is_a: MOD:00911
+is_a: MOD:00883 ! C1-amidated residue
+is_a: MOD:00911 ! modified L-leucine residue
 
 [Term]
 id: MOD:00101
@@ -2579,8 +2579,8 @@ property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0168
-is_a: MOD:00883
-is_a: MOD:00912
+is_a: MOD:00883 ! C1-amidated residue
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:00102
@@ -2604,8 +2604,8 @@ property_value: Origin "M" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0164
-is_a: MOD:00883
-is_a: MOD:00913
+is_a: MOD:00883 ! C1-amidated residue
+is_a: MOD:00913 ! modified L-methionine residue
 
 [Term]
 id: MOD:00103
@@ -2628,8 +2628,8 @@ property_value: Origin "F" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0248
-is_a: MOD:00883
-is_a: MOD:00914
+is_a: MOD:00883 ! C1-amidated residue
+is_a: MOD:00914 ! modified L-phenylalanine residue
 
 [Term]
 id: MOD:00104
@@ -2652,8 +2652,8 @@ property_value: Origin "P" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0257
-is_a: MOD:00883
-is_a: MOD:00915
+is_a: MOD:00883 ! C1-amidated residue
+is_a: MOD:00915 ! modified L-proline residue
 
 [Term]
 id: MOD:00105
@@ -2676,8 +2676,8 @@ property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0275
-is_a: MOD:00883
-is_a: MOD:00916
+is_a: MOD:00883 ! C1-amidated residue
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:00106
@@ -2700,8 +2700,8 @@ property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0293
-is_a: MOD:00883
-is_a: MOD:00917
+is_a: MOD:00883 ! C1-amidated residue
+is_a: MOD:00917 ! modified L-threonine residue
 
 [Term]
 id: MOD:00107
@@ -2724,8 +2724,8 @@ property_value: Origin "W" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0296
-is_a: MOD:00883
-is_a: MOD:00918
+is_a: MOD:00883 ! C1-amidated residue
+is_a: MOD:00918 ! modified L-tryptophan residue
 
 [Term]
 id: MOD:00108
@@ -2748,8 +2748,8 @@ property_value: Origin "Y" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0302
-is_a: MOD:00883
-is_a: MOD:00919
+is_a: MOD:00883 ! C1-amidated residue
+is_a: MOD:00919 ! modified L-tyrosine residue
 
 [Term]
 id: MOD:00109
@@ -2771,8 +2771,8 @@ property_value: Origin "V" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0303
-is_a: MOD:00883
-is_a: MOD:00920
+is_a: MOD:00883 ! C1-amidated residue
+is_a: MOD:00920 ! modified L-valine residue
 
 [Term]
 id: MOD:00110
@@ -2805,10 +2805,10 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:39
 xref: uniprot.ptm:PTM-0104
-is_a: MOD:00848
-is_a: MOD:00905
-is_a: MOD:01153
-is_a: MOD:01862
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00905 ! modified L-cysteine residue
+is_a: MOD:01153 ! methylthiolated residue
+is_a: MOD:01862 ! disulfide conjugated residue
 
 [Term]
 id: MOD:00111
@@ -2835,8 +2835,8 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:44
 xref: uniprot.ptm:PTM-0277
-is_a: MOD:00437
-is_a: MOD:01110
+is_a: MOD:00437 ! farnesylated residue
+is_a: MOD:01110 ! isoprenylated cysteine
 
 [Term]
 id: MOD:00112
@@ -2859,7 +2859,7 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:376
 xref: uniprot.ptm:PTM-0269
-is_a: MOD:01110
+is_a: MOD:01110 ! isoprenylated cysteine
 
 [Term]
 id: MOD:00113
@@ -2886,8 +2886,8 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:48
 xref: uniprot.ptm:PTM-0278
-is_a: MOD:00441
-is_a: MOD:01110
+is_a: MOD:00441 ! geranylgeranylated residue
+is_a: MOD:01110 ! isoprenylated cysteine
 
 [Term]
 id: MOD:00114
@@ -2917,8 +2917,8 @@ property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: Unimod:34
 xref: uniprot.ptm:PTM-0105
-is_a: MOD:01682
-is_a: MOD:01689
+is_a: MOD:01682 ! monomethylated L-cysteine
+is_a: MOD:01689 ! alpha-carboxyl methylated residue
 
 [Term]
 id: MOD:00115
@@ -2949,8 +2949,8 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:47
 xref: uniprot.ptm:PTM-0281
-is_a: MOD:00653
-is_a: MOD:01684
+is_a: MOD:00653 ! S-palmitoylated residue
+is_a: MOD:01684 ! palmitoylated-L-cysteine
 
 [Term]
 id: MOD:00116
@@ -2970,8 +2970,8 @@ synonym: "SAcyl2GlyceroCys" EXACT PSI-MOD-label []
 xref: uniprot.ptm:PTM-0274
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00905
-is_a: MOD:01155
+is_a: MOD:00905 ! modified L-cysteine residue
+is_a: MOD:01155 ! lipoconjugated residue
 
 [Term]
 id: MOD:00117
@@ -2996,9 +2996,9 @@ property_value: MassMono "214.041213" xsd:float
 property_value: Origin "C, Q" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0156
-is_a: MOD:00395
-is_a: MOD:02046
-is_a: MOD:00946
+is_a: MOD:00395 ! thioester crosslinked residues
+is_a: MOD:02046 ! crosslinked L-glutamine residue
+is_a: MOD:00946 ! crosslinked residues with loss of ammonia
 
 [Term]
 id: MOD:00118
@@ -3021,8 +3021,8 @@ property_value: MassMono "238.052447" xsd:float
 property_value: Origin "C, H" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0005
-is_a: MOD:00687
-is_a: MOD:02048
+is_a: MOD:00687 ! thioether crosslinked residues
+is_a: MOD:02048 ! crosslinked L-histidine residue
 
 [Term]
 id: MOD:00119
@@ -3046,9 +3046,9 @@ property_value: MassAvg "172.20" xsd:float
 property_value: MassMono "172.030649" xsd:float
 property_value: Origin "C, S" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02055
-is_a: MOD:00954
-is_a: MOD:01839
+is_a: MOD:02055 ! crosslinked L-serine residue
+is_a: MOD:00954 ! crosslinked residues with loss of water
+is_a: MOD:01839 ! L-lanthionine
 
 [Term]
 id: MOD:00120
@@ -3078,9 +3078,9 @@ property_value: MassMono "172.030649" xsd:float
 property_value: Origin "C, S" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0164
-is_a: MOD:02055
-is_a: MOD:00954
-is_a: MOD:01841
+is_a: MOD:02055 ! crosslinked L-serine residue
+is_a: MOD:00954 ! crosslinked residues with loss of water
+is_a: MOD:01841 ! lanthionine
 
 [Term]
 id: MOD:00121
@@ -3107,7 +3107,7 @@ property_value: MassMono "186.046299" xsd:float
 property_value: Origin "C, T" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0067
-is_a: MOD:01981
+is_a: MOD:01981 ! 3-methyllanthionine
 
 [Term]
 id: MOD:00122
@@ -3132,8 +3132,8 @@ property_value: MassMono "264.056863" xsd:float
 property_value: Origin "C, Y" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0019
-is_a: MOD:00687
-is_a: MOD:02058
+is_a: MOD:00687 ! thioether crosslinked residues
+is_a: MOD:02058 ! crosslinked L-tyrosine residue
 
 [Term]
 id: MOD:00123
@@ -3160,8 +3160,8 @@ property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:299
 xref: uniprot.ptm:PTM-0191
-is_a: MOD:00912
-is_a: MOD:01152
+is_a: MOD:00912 ! modified L-lysine residue
+is_a: MOD:01152 ! carboxylated residue
 
 [Term]
 id: MOD:00124
@@ -3186,7 +3186,7 @@ property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:378
 xref: uniprot.ptm:PTM-0189
-is_a: MOD:00912
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:00125
@@ -3215,9 +3215,9 @@ property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:379
 xref: uniprot.ptm:PTM-0150
-is_a: MOD:00912
-is_a: MOD:01884
-relationship: derives_from MOD:01880
+is_a: MOD:00912 ! modified L-lysine residue
+is_a: MOD:01884 ! 4-aminobutylated residue
+relationship: derives_from MOD:01880 ! L-deoxyhypusine
 
 [Term]
 id: MOD:00126
@@ -3247,8 +3247,8 @@ property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:3
 xref: uniprot.ptm:PTM-0382
-is_a: MOD:01875
-is_a: MOD:01885
+is_a: MOD:01875 ! N6-acylated L-lysine
+is_a: MOD:01885 ! biotinylated residue
 
 [Term]
 id: MOD:00127
@@ -3278,7 +3278,7 @@ property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:42
 xref: uniprot.ptm:PTM-0383
-is_a: MOD:01875
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:00128
@@ -3303,7 +3303,7 @@ property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:46
 xref: uniprot.ptm:PTM-0387
-is_a: MOD:00912
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:00129
@@ -3328,7 +3328,7 @@ property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:380
 xref: uniprot.ptm:PTM-0388
-is_a: MOD:00912
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:00130
@@ -3361,7 +3361,7 @@ property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:352
 xref: uniprot.ptm:PTM-0059
-is_a: MOD:00912
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:00131
@@ -3386,7 +3386,7 @@ property_value: MassMono "143.058243" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:381
-is_a: MOD:00912
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:00132
@@ -3412,10 +3412,10 @@ property_value: MassMono "197.116427" xsd:float
 property_value: Origin "K, S" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0172
-is_a: MOD:02055
-is_a: MOD:02051
-is_a: MOD:00954
-is_a: MOD:01853
+is_a: MOD:02055 ! crosslinked L-serine residue
+is_a: MOD:02051 ! crosslinked L-lysine residue
+is_a: MOD:00954 ! crosslinked residues with loss of water
+is_a: MOD:01853 ! L-lysinoalanine
 
 [Term]
 id: MOD:00133
@@ -3440,9 +3440,9 @@ property_value: MassMono "239.126991" xsd:float
 property_value: Origin "K, Q" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0158
-is_a: MOD:02046
-is_a: MOD:00946
-is_a: MOD:01630
+is_a: MOD:02046 ! crosslinked L-glutamine residue
+is_a: MOD:00946 ! crosslinked residues with loss of ammonia
+is_a: MOD:01630 ! N6-(L-isoglutamyl)-L-lysine
 
 [Term]
 id: MOD:00134
@@ -3466,11 +3466,11 @@ property_value: Origin "G, K" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0134
-is_a: MOD:00688
-is_a: MOD:02047
-is_a: MOD:02051
-is_a: MOD:00954
-is_a: MOD:01875
+is_a: MOD:00688 ! isopeptide crosslinked residues
+is_a: MOD:02047 ! crosslinked glycine residue
+is_a: MOD:02051 ! crosslinked L-lysine residue
+is_a: MOD:00954 ! crosslinked residues with loss of water
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:00135
@@ -3496,9 +3496,9 @@ property_value: Origin "G, N" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0489
-is_a: MOD:02042
-is_a: MOD:00946
-is_a: MOD:01928
+is_a: MOD:02042 ! crosslinked L-asparagine residue
+is_a: MOD:00946 ! crosslinked residues with loss of ammonia
+is_a: MOD:01928 ! N-(L-isoaspartyl)-glycine
 
 [Term]
 id: MOD:00136
@@ -3520,8 +3520,8 @@ property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:382
 xref: uniprot.ptm:PTM-0265
-is_a: MOD:00905
-is_a: MOD:01154
+is_a: MOD:00905 ! modified L-cysteine residue
+is_a: MOD:01154 ! pyruvic acid
 
 [Term]
 id: MOD:00137
@@ -3543,7 +3543,7 @@ property_value: Origin "F" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:7
 xref: uniprot.ptm:PTM-0035
-is_a: MOD:00914
+is_a: MOD:00914 ! modified L-phenylalanine residue
 
 [Term]
 id: MOD:00138
@@ -3566,8 +3566,8 @@ property_value: Origin "T" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:385
 xref: uniprot.ptm:PTM-0017
-is_a: MOD:00917
-is_a: MOD:01160
+is_a: MOD:00917 ! modified L-threonine residue
+is_a: MOD:01160 ! deaminated residue
 
 [Term]
 id: MOD:00139
@@ -3590,8 +3590,8 @@ property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:64
 xref: uniprot.ptm:PTM-0181
-is_a: MOD:02081
-is_a: MOD:00918
+is_a: MOD:02081 ! alpha-amino succinylated residue
+is_a: MOD:00918 ! modified L-tryptophan residue
 
 [Term]
 id: MOD:00140
@@ -3617,8 +3617,8 @@ property_value: MassMono "689.288320" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:387
-is_a: MOD:00700
-is_a: MOD:00905
+is_a: MOD:00700 ! tetrapyrrole modified residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00141
@@ -3641,8 +3641,8 @@ property_value: MassMono "691.303970" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:388
-is_a: MOD:00700
-is_a: MOD:00905
+is_a: MOD:00700 ! tetrapyrrole modified residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00142
@@ -3665,8 +3665,8 @@ property_value: MassMono "687.272670" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:389
-is_a: MOD:00700
-is_a: MOD:00905
+is_a: MOD:00700 ! tetrapyrrole modified residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00143
@@ -3688,8 +3688,8 @@ property_value: MassAvg "822.78" xsd:float
 property_value: MassMono "822.195663" xsd:float
 property_value: Origin "C, C" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00699
-is_a: MOD:02067
+is_a: MOD:00699 ! porphyrin modified residue
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
 
 [Term]
 id: MOD:00144
@@ -3715,8 +3715,8 @@ property_value: MassMono "719.186478" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:390
-is_a: MOD:00699
-is_a: MOD:02067
+is_a: MOD:00699 ! porphyrin modified residue
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
 
 [Term]
 id: MOD:00145
@@ -3735,8 +3735,8 @@ property_value: MassAvg "464.37" xsd:float
 property_value: MassMono "463.941474" xsd:float
 property_value: Origin "C, C, C, C" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00738
-is_a: MOD:02067
+is_a: MOD:00738 ! iron containing modified residue
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
 
 [Term]
 id: MOD:00146
@@ -3756,8 +3756,8 @@ property_value: MassAvg "584.34" xsd:float
 property_value: MassMono "583.820553" xsd:float
 property_value: Origin "C, C, C, C" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00739
-is_a: MOD:02067
+is_a: MOD:00739 ! iron-sulfur cluster containing modification
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
 
 [Term]
 id: MOD:00147
@@ -3776,8 +3776,8 @@ property_value: MassAvg "876.50" xsd:float
 property_value: MassMono "875.730830" xsd:float
 property_value: Origin "C, C, C, C, C, C" xsd:string
 property_value: Source "hypothetical" xsd:string
-is_a: MOD:00739
-is_a: MOD:02067
+is_a: MOD:00739 ! iron-sulfur cluster containing modification
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
 
 [Term]
 id: MOD:00148
@@ -3801,8 +3801,8 @@ property_value: MassAvg "602.17" xsd:float
 property_value: MassMono "601.698821" xsd:float
 property_value: Origin "C, C, C" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00739
-is_a: MOD:02067
+is_a: MOD:00739 ! iron-sulfur cluster containing modification
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
 
 [Term]
 id: MOD:00149
@@ -3823,8 +3823,8 @@ property_value: MassAvg "760.15" xsd:float
 property_value: MassMono "759.634570" xsd:float
 property_value: Origin "C, C, C, C" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00739
-is_a: MOD:02067
+is_a: MOD:00739 ! iron-sulfur cluster containing modification
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
 
 [Term]
 id: MOD:00150
@@ -3842,10 +3842,10 @@ property_value: MassAvg "1231.81" xsd:float
 property_value: MassMono "1233.281133" xsd:float
 property_value: Origin "C, H" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00739
-is_a: MOD:00743
-is_a: MOD:02067
-is_a: MOD:02070
+is_a: MOD:00739 ! iron-sulfur cluster containing modification
+is_a: MOD:00743 ! molybdenum containing modified residue
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
+is_a: MOD:02070 ! metal or metal cluster coordinated L-histidine residue
 
 [Term]
 id: MOD:00151
@@ -3870,9 +3870,9 @@ property_value: MassMono "624.893259" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:391
-is_a: MOD:00744
-is_a: MOD:00861
-is_a: MOD:02067
+is_a: MOD:00744 ! molybdenum pterin containing modification
+is_a: MOD:00861 ! phosphorus containing modified residue
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
 
 [Term]
 id: MOD:00152
@@ -3896,8 +3896,8 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:50
 xref: uniprot.ptm:PTM-0272
-is_a: MOD:00895
-is_a: MOD:00905
+is_a: MOD:00895 ! FAD modified residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00153
@@ -3925,8 +3925,8 @@ property_value: Origin "H" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:50
 xref: uniprot.ptm:PTM-0258
-is_a: MOD:00895
-is_a: MOD:00909
+is_a: MOD:00895 ! FAD modified residue
+is_a: MOD:00909 ! modified L-histidine residue
 
 [Term]
 id: MOD:00154
@@ -3952,8 +3952,8 @@ property_value: Origin "Y" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:50
 xref: uniprot.ptm:PTM-0231
-is_a: MOD:00895
-is_a: MOD:00919
+is_a: MOD:00895 ! FAD modified residue
+is_a: MOD:00919 ! modified L-tyrosine residue
 
 [Term]
 id: MOD:00155
@@ -3981,8 +3981,8 @@ property_value: Origin "Y" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:35
 xref: uniprot.ptm:PTM-0023
-is_a: MOD:00425
-is_a: MOD:00707
+is_a: MOD:00425 ! monohydroxylated residue
+is_a: MOD:00707 ! hydroxylated tyrosine
 
 [Term]
 id: MOD:00156
@@ -4009,8 +4009,8 @@ property_value: Origin "Y" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:392
 xref: uniprot.ptm:PTM-0009
-is_a: MOD:00679
-is_a: MOD:00919
+is_a: MOD:00679 ! carbon oxygenated residue
+is_a: MOD:00919 ! modified L-tyrosine residue
 
 [Term]
 id: MOD:00157
@@ -4038,8 +4038,8 @@ property_value: Origin "W" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:392
 xref: uniprot.ptm:PTM-0299
-is_a: MOD:00679
-is_a: MOD:00918
+is_a: MOD:00679 ! carbon oxygenated residue
+is_a: MOD:00918 ! modified L-tryptophan residue
 
 [Term]
 id: MOD:00158
@@ -4066,8 +4066,8 @@ property_value: MassMono "400.117155" xsd:float
 property_value: Origin "W, W" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0298
-is_a: MOD:00692
-is_a: MOD:02057
+is_a: MOD:00692 ! uncategorized crosslinked residues
+is_a: MOD:02057 ! crosslinked L-tryptophan residue
 
 [Term]
 id: MOD:00159
@@ -4092,8 +4092,8 @@ property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:49
 xref: uniprot.ptm:PTM-0391
-is_a: MOD:00861
-is_a: MOD:00916
+is_a: MOD:00861 ! phosphorus containing modified residue
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:00160
@@ -4103,8 +4103,8 @@ subset: PSI-MOD-slim
 synonym: "N4GlycoAsn" EXACT PSI-MOD-label []
 property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00006
-is_a: MOD:00903
+is_a: MOD:00006 ! N-glycosylated residue
+is_a: MOD:00903 ! modified L-asparagine residue
 
 [Term]
 id: MOD:00161
@@ -4128,9 +4128,9 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:41
 xref: uniprot.ptm:PTM-0626
-is_a: MOD:00426
-is_a: MOD:00433
-is_a: MOD:00905
+is_a: MOD:00426 ! S-glycosylated residue
+is_a: MOD:00433 ! monoglucosylated residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00162
@@ -4153,9 +4153,9 @@ property_value: MassMono "468.195524" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:393
-relationship: derives_from MOD:00037
-is_a: MOD:00912
-is_a: MOD:00396
+relationship: derives_from MOD:00037 ! 5-hydroxy-L-lysine
+is_a: MOD:00912 ! modified L-lysine residue
+is_a: MOD:00396 ! O-glycosylated residue
 
 [Term]
 id: MOD:00163
@@ -4178,8 +4178,8 @@ property_value: MassMono "290.111401" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0564
-is_a: MOD:00563
-is_a: MOD:01675
+is_a: MOD:00563 ! mono-N-acetylaminogalactosylated residue
+is_a: MOD:01675 ! O-(N-acetylamino)hexosyl-L-serine
 
 [Term]
 id: MOD:00164
@@ -4203,8 +4203,8 @@ property_value: MassMono "304.127051" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0567
-is_a: MOD:00563
-is_a: MOD:01676
+is_a: MOD:00563 ! mono-N-acetylaminogalactosylated residue
+is_a: MOD:01676 ! O-(N-acetylamino)hexosyl-L-threonine
 
 [Term]
 id: MOD:00165
@@ -4227,9 +4227,9 @@ property_value: MassMono "348.132136" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0535
-is_a: MOD:00006
-is_a: MOD:00595
-is_a: MOD:00918
+is_a: MOD:00006 ! N-glycosylated residue
+is_a: MOD:00595 ! monomannosylated residue
+is_a: MOD:00918 ! modified L-tryptophan residue
 
 [Term]
 id: MOD:00166
@@ -4252,8 +4252,8 @@ property_value: Origin "Y" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:41
 xref: uniprot.ptm:PTM-0575
-is_a: MOD:00433
-is_a: MOD:01927
+is_a: MOD:00433 ! monoglucosylated residue
+is_a: MOD:01927 ! O-glycosyl-L-tyrosine
 
 [Term]
 id: MOD:00167
@@ -4272,8 +4272,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0137
-is_a: MOD:00818
-is_a: MOD:00903
+is_a: MOD:00818 ! glycosylphosphatidylinositolated residue
+is_a: MOD:00903 ! modified L-asparagine residue
 
 [Term]
 id: MOD:00168
@@ -4292,8 +4292,8 @@ property_value: Origin "D" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0138
-is_a: MOD:00818
-is_a: MOD:00904
+is_a: MOD:00818 ! glycosylphosphatidylinositolated residue
+is_a: MOD:00904 ! modified L-aspartic acid residue
 
 [Term]
 id: MOD:00169
@@ -4312,8 +4312,8 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0140
-is_a: MOD:00818
-is_a: MOD:00905
+is_a: MOD:00818 ! glycosylphosphatidylinositolated residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00170
@@ -4332,8 +4332,8 @@ property_value: Origin "G" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0141
-is_a: MOD:00818
-is_a: MOD:00908
+is_a: MOD:00818 ! glycosylphosphatidylinositolated residue
+is_a: MOD:00908 ! modified glycine residue
 
 [Term]
 id: MOD:00171
@@ -4352,8 +4352,8 @@ property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0142
-is_a: MOD:00818
-is_a: MOD:00916
+is_a: MOD:00818 ! glycosylphosphatidylinositolated residue
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:00172
@@ -4372,8 +4372,8 @@ property_value: Origin "A" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0136
-is_a: MOD:00818
-is_a: MOD:00901
+is_a: MOD:00818 ! glycosylphosphatidylinositolated residue
+is_a: MOD:00901 ! modified L-alanine residue
 
 [Term]
 id: MOD:00173
@@ -4392,8 +4392,8 @@ property_value: Origin "T" xsd:string
 property_value: Source "hypothetical" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0143
-is_a: MOD:00818
-is_a: MOD:00917
+is_a: MOD:00818 ! glycosylphosphatidylinositolated residue
+is_a: MOD:00917 ! modified L-threonine residue
 
 [Term]
 id: MOD:00174
@@ -4412,8 +4412,8 @@ property_value: Origin "G" xsd:string
 property_value: Source "hypothetical" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0146
-is_a: MOD:00466
-is_a: MOD:00908
+is_a: MOD:00466 ! glycosylsphingolipidinositolated residue
+is_a: MOD:00908 ! modified glycine residue
 
 [Term]
 id: MOD:00175
@@ -4432,8 +4432,8 @@ property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0147
-is_a: MOD:00466
-is_a: MOD:00916
+is_a: MOD:00466 ! glycosylsphingolipidinositolated residue
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:00176
@@ -4459,9 +4459,9 @@ property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:395
 xref: uniprot.ptm:PTM-0389
-is_a: MOD:00860
-is_a: MOD:00861
-is_a: MOD:00916
+is_a: MOD:00860 ! sulfur containing modified residue
+is_a: MOD:00861 ! phosphorus containing modified residue
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:00177
@@ -4488,8 +4488,8 @@ property_value: Origin "R" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:213
 xref: uniprot.ptm:PTM-0053
-is_a: MOD:00752
-is_a: MOD:00902
+is_a: MOD:00752 ! monoadenosine diphosphoribosyl (ADP-ribosyl) modified residue
+is_a: MOD:00902 ! modified L-arginine residue
 
 [Term]
 id: MOD:00178
@@ -4516,8 +4516,8 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:213
 xref: uniprot.ptm:PTM-0055
-is_a: MOD:00752
-is_a: MOD:00905
+is_a: MOD:00752 ! monoadenosine diphosphoribosyl (ADP-ribosyl) modified residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00179
@@ -4544,7 +4544,7 @@ property_value: Origin "E" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:396
 xref: uniprot.ptm:PTM-0403
-is_a: MOD:00906
+is_a: MOD:00906 ! modified L-glutamic acid residue
 
 [Term]
 id: MOD:00180
@@ -4570,9 +4570,9 @@ property_value: MassMono "182.966000" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:40
-is_a: MOD:00695
-is_a: MOD:00777
-is_a: MOD:00905
+is_a: MOD:00695 ! sulfated residue
+is_a: MOD:00777 ! residues isobaric at 182.96-182.98 Da
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00181
@@ -4604,9 +4604,9 @@ property_value: Origin "Y" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:40
 xref: uniprot.ptm:PTM-0286
-is_a: MOD:00695
-is_a: MOD:00774
-is_a: MOD:00919
+is_a: MOD:00695 ! sulfated residue
+is_a: MOD:00774 ! residues isobaric at 243.02-243.03 Da
+is_a: MOD:00919 ! modified L-tyrosine residue
 
 [Term]
 id: MOD:00182
@@ -4627,8 +4627,8 @@ property_value: Origin "H" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:340
 xref: uniprot.ptm:PTM-0089
-is_a: MOD:01049
-is_a: MOD:01912
+is_a: MOD:01049 ! halogenated histidine
+is_a: MOD:01912 ! monobrominated residue
 
 [Term]
 id: MOD:00183
@@ -4651,7 +4651,7 @@ property_value: MassAvg "226.07" xsd:float
 property_value: MassMono "224.978926" xsd:float
 property_value: Origin "F" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00972
+is_a: MOD:00972 ! monobrominated L-phenylalanine
 
 [Term]
 id: MOD:00184
@@ -4672,7 +4672,7 @@ property_value: MassAvg "226.07" xsd:float
 property_value: MassMono "224.978926" xsd:float
 property_value: Origin "F" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00972
+is_a: MOD:00972 ! monobrominated L-phenylalanine
 
 [Term]
 id: MOD:00185
@@ -4693,7 +4693,7 @@ property_value: MassAvg "226.07" xsd:float
 property_value: MassMono "224.978926" xsd:float
 property_value: Origin "F" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00972
+is_a: MOD:00972 ! monobrominated L-phenylalanine
 
 [Term]
 id: MOD:00186
@@ -4724,7 +4724,7 @@ property_value: Origin "Y" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:397
 xref: uniprot.ptm:PTM-0295
-is_a: MOD:00998
+is_a: MOD:00998 ! iodinated tyrosine
 
 [Term]
 id: MOD:00187
@@ -4753,7 +4753,7 @@ property_value: Origin "Y" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:398
 xref: uniprot.ptm:PTM-0294
-is_a: MOD:00998
+is_a: MOD:00998 ! iodinated tyrosine
 
 [Term]
 id: MOD:00188
@@ -4775,8 +4775,8 @@ property_value: Origin "W" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:398
 xref: uniprot.ptm:PTM-0051
-is_a: MOD:01068
-is_a: MOD:01912
+is_a: MOD:01068 ! halogenated tryptophan
+is_a: MOD:01912 ! monobrominated residue
 
 [Term]
 id: MOD:00189
@@ -4806,9 +4806,9 @@ property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:23
 xref: uniprot.ptm:PTM-0006
-is_a: MOD:00416
-is_a: MOD:00916
-is_a: MOD:01168
+is_a: MOD:00416 ! phosphorylation of an hydroxyl amino acid with prompt loss of phosphate
+is_a: MOD:00916 ! modified L-serine residue
+is_a: MOD:01168 ! dehydroalanine
 
 [Term]
 id: MOD:00190
@@ -4832,7 +4832,7 @@ synonym: "Dehydroamino butyric acid" EXACT DeltaMass-label []
 synonym: "Dhb" EXACT RESID-alternate []
 synonym: "Dhb(Thr)" EXACT PSI-MOD-label []
 synonym: "methyl-dehydroalanine" EXACT RESID-alternate []
-synonym: "MOD_RES (Z)-2,3-didehydrobutyrine" EXACT UniProt-feature []
+synonym: "MOD_RES 2,3-didehydrobutyrine" EXACT UniProt-feature []
 synonym: "phospholosst" EXACT OMSSA-label []
 property_value: DiffAvg "-18.02" xsd:float
 property_value: DiffFormula "C 0 H -2 N 0 O -1" xsd:string
@@ -4844,9 +4844,9 @@ property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:23
 xref: uniprot.ptm:PTM-0007
-is_a: MOD:00416
-is_a: MOD:00917
-is_a: MOD:01703
+is_a: MOD:00416 ! phosphorylation of an hydroxyl amino acid with prompt loss of phosphate
+is_a: MOD:00917 ! modified L-threonine residue
+is_a: MOD:01703 ! dehydrobutyrine
 
 [Term]
 id: MOD:00191
@@ -4875,7 +4875,7 @@ property_value: MassMono "161.047678" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0002
-is_a: MOD:00706
+is_a: MOD:00706 ! dehydrogenated tyrosine
 
 [Term]
 id: MOD:00192
@@ -4899,10 +4899,10 @@ property_value: MassMono "126.042927" xsd:float
 property_value: Origin "G, S" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0049
-is_a: MOD:02047
-is_a: MOD:02055
-is_a: MOD:01882
-is_a: MOD:00954
+is_a: MOD:02047 ! crosslinked glycine residue
+is_a: MOD:02055 ! crosslinked L-serine residue
+is_a: MOD:01882 ! 5-imidazolinone ring crosslinked residues (Gly)
+is_a: MOD:00954 ! crosslinked residues with loss of water
 
 [Term]
 id: MOD:00193
@@ -4928,7 +4928,7 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:402
 xref: uniprot.ptm:PTM-0034
-is_a: MOD:01169
+is_a: MOD:01169 ! L-3-oxoalanine
 
 [Term]
 id: MOD:00194
@@ -4952,7 +4952,7 @@ property_value: Origin "S" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:403
 xref: uniprot.ptm:PTM-0163
-is_a: MOD:00916
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:00195
@@ -4976,10 +4976,10 @@ property_value: MassMono "110.048013" xsd:float
 property_value: Origin "A, G" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0045
-is_a: MOD:02040
-is_a: MOD:02047
-is_a: MOD:01882
-is_a: MOD:00954
+is_a: MOD:02040 ! crosslinked L-alanine residue
+is_a: MOD:02047 ! crosslinked glycine residue
+is_a: MOD:01882 ! 5-imidazolinone ring crosslinked residues (Gly)
+is_a: MOD:00954 ! crosslinked residues with loss of water
 
 [Term]
 id: MOD:00196
@@ -5003,10 +5003,10 @@ property_value: MassMono "142.020084" xsd:float
 property_value: Origin "C, G" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0047
-is_a: MOD:02044
-is_a: MOD:02047
-is_a: MOD:01882
-is_a: MOD:00954
+is_a: MOD:02044 ! crosslinked L-cysteine residue
+is_a: MOD:02047 ! crosslinked glycine residue
+is_a: MOD:01882 ! 5-imidazolinone ring crosslinked residues (Gly)
+is_a: MOD:00954 ! crosslinked residues with loss of water
 
 [Term]
 id: MOD:00197
@@ -5031,9 +5031,9 @@ property_value: MassMono "165.053826" xsd:float
 property_value: Origin "G, Q" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0013
-is_a: MOD:02046
-is_a: MOD:02047
-is_a: MOD:01882
+is_a: MOD:02046 ! crosslinked L-glutamine residue
+is_a: MOD:02047 ! crosslinked glycine residue
+is_a: MOD:01882 ! 5-imidazolinone ring crosslinked residues (Gly)
 
 [Term]
 id: MOD:00198
@@ -5052,9 +5052,9 @@ property_value: MassMono "71.037114" xsd:float
 property_value: Origin "A" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0112
-is_a: MOD:00570
-is_a: MOD:00862
-is_a: MOD:00901
+is_a: MOD:00570 ! residues isobaric at 71.037114 Da
+is_a: MOD:00862 ! D-alanine
+is_a: MOD:00901 ! modified L-alanine residue
 
 [Term]
 id: MOD:00199
@@ -5078,9 +5078,9 @@ property_value: MassMono "113.084064" xsd:float
 property_value: Origin "I" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0114
-is_a: MOD:00306
-is_a: MOD:00664
-is_a: MOD:00910
+is_a: MOD:00306 ! residues isobaric at 113.084064 Da
+is_a: MOD:00664 ! stereoisomerized residue
+is_a: MOD:00910 ! modified L-isoleucine residue
 
 [Term]
 id: MOD:00200
@@ -5101,8 +5101,8 @@ property_value: MassMono "131.040485" xsd:float
 property_value: Origin "M" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0120
-is_a: MOD:00664
-is_a: MOD:00913
+is_a: MOD:00664 ! stereoisomerized residue
+is_a: MOD:00913 ! modified L-methionine residue
 
 [Term]
 id: MOD:00201
@@ -5121,8 +5121,8 @@ property_value: MassMono "147.068414" xsd:float
 property_value: Origin "F" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0121
-is_a: MOD:00664
-is_a: MOD:00914
+is_a: MOD:00664 ! stereoisomerized residue
+is_a: MOD:00914 ! modified L-phenylalanine residue
 
 [Term]
 id: MOD:00202
@@ -5141,8 +5141,8 @@ property_value: MassMono "87.032028" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0308
-is_a: MOD:00891
-is_a: MOD:00916
+is_a: MOD:00891 ! D-serine
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:00203
@@ -5164,8 +5164,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0115
-is_a: MOD:00664
-is_a: MOD:00903
+is_a: MOD:00664 ! stereoisomerized residue
+is_a: MOD:00903 ! modified L-asparagine residue
 
 [Term]
 id: MOD:00204
@@ -5185,9 +5185,9 @@ property_value: MassMono "113.084064" xsd:float
 property_value: Origin "L" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0119
-is_a: MOD:00306
-is_a: MOD:00664
-is_a: MOD:00911
+is_a: MOD:00306 ! residues isobaric at 113.084064 Da
+is_a: MOD:00664 ! stereoisomerized residue
+is_a: MOD:00911 ! modified L-leucine residue
 
 [Term]
 id: MOD:00205
@@ -5207,8 +5207,8 @@ property_value: MassMono "186.079313" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0123
-is_a: MOD:00664
-is_a: MOD:00918
+is_a: MOD:00664 ! stereoisomerized residue
+is_a: MOD:00918 ! modified L-tryptophan residue
 
 [Term]
 id: MOD:00206
@@ -5220,7 +5220,7 @@ synonym: "MOD_RES 5-glutamyl polyglycine" EXACT UniProt-feature []
 property_value: Origin "E" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0394
-is_a: MOD:00906
+is_a: MOD:00906 ! modified L-glutamic acid residue
 
 [Term]
 id: MOD:00207
@@ -5231,7 +5231,7 @@ synonym: "L-isoglutamyl-polyglutamic acid" EXACT RESID-name []
 property_value: Origin "E" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0395
-is_a: MOD:00906
+is_a: MOD:00906 ! modified L-glutamic acid residue
 
 [Term]
 id: MOD:00208
@@ -5259,8 +5259,8 @@ property_value: Origin "Y" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:405
 xref: uniprot.ptm:PTM-0332
-is_a: MOD:00919
-is_a: MOD:01165
+is_a: MOD:00919 ! modified L-tyrosine residue
+is_a: MOD:01165 ! adenylated residue
 
 [Term]
 id: MOD:00209
@@ -5281,8 +5281,8 @@ property_value: MassMono "143.027909" xsd:float
 property_value: Origin "C, S" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0268
-is_a: MOD:02055
-is_a: MOD:01850
+is_a: MOD:02055 ! crosslinked L-serine residue
+is_a: MOD:01850 ! S-(2-aminovinyl)-D-cysteine
 
 [Term]
 id: MOD:00210
@@ -5318,8 +5318,8 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:35
 xref: uniprot.ptm:PTM-0107
-is_a: MOD:00708
-is_a: MOD:01854
+is_a: MOD:00708 ! sulfur oxygenated L-cysteine
+is_a: MOD:01854 ! sulfur monooxygenated residue
 
 [Term]
 id: MOD:00211
@@ -5343,9 +5343,9 @@ property_value: MassMono "159.022823" xsd:float
 property_value: Origin "C, G" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0429
-is_a: MOD:00395
-is_a: MOD:02047
-is_a: MOD:00954
+is_a: MOD:00395 ! thioester crosslinked residues
+is_a: MOD:02047 ! crosslinked glycine residue
+is_a: MOD:00954 ! crosslinked residues with loss of water
 
 [Term]
 id: MOD:00212
@@ -5368,7 +5368,7 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:407
 xref: uniprot.ptm:PTM-0414
-is_a: MOD:00905
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00213
@@ -5380,7 +5380,7 @@ synonym: "chondroitin sulfate D-glucuronosyl-D-galactosyl-D-galactosyl-D-xylosyl
 synonym: "poly[beta-1,4-D-glucopyranuronosyl-beta-1,3-(2-acetamido-2-deoxy-4-sulfate-D-galactosyl)]-beta-1,4-D-glucopyranuronosyl-beta-1,3-D-galactosyl-beta-1,3-D-galactosyl-beta-1,4-D-xylosyl-beta-1,3-L-serine; poly[beta-1,4-D-glucopyranuronosyl-beta-1,3-(2-acetamido-2-deoxy-6-sulfate D-galactosyl)]-beta-1,4-D-glucopyranuronosyl-beta-1,3-D-galactosyl-beta-1,3-D-galactosyl-beta-1,4-D-xylosyl-beta-1,3-L-serine" EXACT RESID-systematic []
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00002
+is_a: MOD:00002 ! O-glycosyl-L-serine
 
 [Term]
 id: MOD:00214
@@ -5392,7 +5392,7 @@ synonym: "dermatan 4-sulfate D-glucuronosyl-D-galactosyl-D-galactosyl-D-xylosyl-
 synonym: "poly[beta-1,4-L-idopyranuronosyl-alpha-1,3-(2-acetamido-2-deoxy-4-sulfate D-galactosyl)]-beta-1,4-D-glucopyranuronosyl-beta-1,3-D-galactosyl-beta-1,3-D-galactosyl-beta-1,4-D-xylosyl-beta-1,3-L-serine" EXACT RESID-systematic []
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00002
+is_a: MOD:00002 ! O-glycosyl-L-serine
 
 [Term]
 id: MOD:00215
@@ -5404,7 +5404,7 @@ synonym: "heparitin sulfate" EXACT RESID-alternate []
 synonym: "poly[alpha-1,4-(2-sulfate D-glucopyranuronosyl)-beta-1,4-(2-sulfamino-2-deoxy-6-sulfate D-glucosyl)]-beta-1,4-D-glucopyranuronosyl-beta-1,3-D-galactosyl-beta-1,3-D-galactosyl-beta-1,4-D-xylosyl-beta-1,3-L-serine" EXACT RESID-systematic []
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00002
+is_a: MOD:00002 ! O-glycosyl-L-serine
 
 [Term]
 id: MOD:00216
@@ -5431,8 +5431,8 @@ property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:122
 xref: uniprot.ptm:PTM-0192
-is_a: MOD:00409
-is_a: MOD:01875
+is_a: MOD:00409 ! N-formylated residue
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:00217
@@ -5459,8 +5459,8 @@ property_value: Origin "P" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:408
 xref: uniprot.ptm:PTM-0545
-is_a: MOD:00396
-is_a: MOD:00915
+is_a: MOD:00396 ! O-glycosylated residue
+is_a: MOD:00915 ! modified L-proline residue
 
 [Term]
 id: MOD:00218
@@ -5474,8 +5474,8 @@ synonym: "O3-L-serine 5'-RNA phosphodiester" EXACT RESID-alternate []
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0227
-is_a: MOD:00751
-is_a: MOD:00916
+is_a: MOD:00751 ! ribonucleic acid linked residue
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:00219
@@ -5508,7 +5508,7 @@ property_value: Origin "R" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:7
 xref: uniprot.ptm:PTM-0092
-is_a: MOD:00902
+is_a: MOD:00902 ! modified L-arginine residue
 
 [Term]
 id: MOD:00220
@@ -5533,8 +5533,8 @@ property_value: MassMono "172.096026" xsd:float
 property_value: Origin "R" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0042
-is_a: MOD:00425
-is_a: MOD:00682
+is_a: MOD:00425 ! monohydroxylated residue
+is_a: MOD:00682 ! hydroxylated arginine
 
 [Term]
 id: MOD:00221
@@ -5558,10 +5558,10 @@ property_value: Origin "C, N" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0151
-is_a: MOD:02042
-is_a: MOD:02044
-is_a: MOD:00946
-is_a: MOD:00688
+is_a: MOD:02042 ! crosslinked L-asparagine residue
+is_a: MOD:02044 ! crosslinked L-cysteine residue
+is_a: MOD:00946 ! crosslinked residues with loss of ammonia
+is_a: MOD:00688 ! isopeptide crosslinked residues
 
 [Term]
 id: MOD:00222
@@ -5584,9 +5584,9 @@ property_value: Origin "W" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:41
 xref: uniprot.ptm:PTM-0505
-is_a: MOD:00421
-is_a: MOD:00595
-is_a: MOD:00918
+is_a: MOD:00421 ! C-glycosylated residue
+is_a: MOD:00595 ! monomannosylated residue
+is_a: MOD:00918 ! modified L-tryptophan residue
 
 [Term]
 id: MOD:00223
@@ -5598,8 +5598,8 @@ synonym: "N6-mureinyl-L-lysine" EXACT RESID-name []
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0195
-is_a: MOD:01159
-is_a: MOD:01875
+is_a: MOD:01159 ! peptidoglycanated residue
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:00224
@@ -5613,7 +5613,7 @@ synonym: "protein-glycosaminoglycan-protein cross-link" EXACT RESID-alternate []
 property_value: Origin "D" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0334
-is_a: MOD:00904
+is_a: MOD:00904 ! modified L-aspartic acid residue
 
 [Term]
 id: MOD:00225
@@ -5638,8 +5638,8 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:409
 xref: uniprot.ptm:PTM-0271
-is_a: MOD:02084
-is_a: MOD:00905
+is_a: MOD:02084 ! 6-FMN modified residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00226
@@ -5669,8 +5669,8 @@ property_value: Origin "H" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:50
 xref: uniprot.ptm:PTM-0288
-is_a: MOD:00895
-is_a: MOD:00909
+is_a: MOD:00895 ! FAD modified residue
+is_a: MOD:00909 ! modified L-histidine residue
 
 [Term]
 id: MOD:00227
@@ -5699,8 +5699,8 @@ property_value: Origin "R" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:21
 xref: uniprot.ptm:PTM-0250
-is_a: MOD:00902
-is_a: MOD:01456
+is_a: MOD:00902 ! modified L-arginine residue
+is_a: MOD:01456 ! N-phosphorylated residue
 
 [Term]
 id: MOD:00228
@@ -5726,8 +5726,8 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:410
 xref: uniprot.ptm:PTM-0273
-is_a: MOD:00905
-is_a: MOD:01155
+is_a: MOD:00905 ! modified L-cysteine residue
+is_a: MOD:01155 ! lipoconjugated residue
 
 [Term]
 id: MOD:00229
@@ -5744,7 +5744,7 @@ property_value: MassAvg "204.26" xsd:float
 property_value: MassMono "204.002720" xsd:float
 property_value: Origin "C, C" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:02044
+is_a: MOD:02044 ! crosslinked L-cysteine residue
 
 [Term]
 id: MOD:00230
@@ -5765,9 +5765,9 @@ property_value: MassAvg "652.34" xsd:float
 property_value: MassMono "651.920007" xsd:float
 property_value: Origin "C, C, H, H" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00739
-is_a: MOD:02067
-is_a: MOD:02070
+is_a: MOD:00739 ! iron-sulfur cluster containing modification
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
+is_a: MOD:02070 ! metal or metal cluster coordinated L-histidine residue
 
 [Term]
 id: MOD:00231
@@ -5787,8 +5787,8 @@ property_value: MassAvg "1140.22" xsd:float
 property_value: MassMono "1139.450758" xsd:float
 property_value: Origin "C, C, C, C, C, C" xsd:string
 property_value: Source "hypothetical" xsd:string
-is_a: MOD:00739
-is_a: MOD:02067
+is_a: MOD:00739 ! iron-sulfur cluster containing modification
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
 
 [Term]
 id: MOD:00232
@@ -5816,8 +5816,8 @@ property_value: MassMono "457.147483" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:405
-is_a: MOD:00912
-is_a: MOD:01165
+is_a: MOD:00912 ! modified L-lysine residue
+is_a: MOD:01165 ! adenylated residue
 
 [Term]
 id: MOD:00233
@@ -5848,14 +5848,13 @@ property_value: MassMono "473.142397" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:413
-is_a: MOD:00912
-is_a: MOD:01163
+is_a: MOD:00912 ! modified L-lysine residue
+is_a: MOD:01163 ! guanylated residue
 
 [Term]
 id: MOD:00234
 name: L-cysteine glutathione disulfide
 def: "A protein modification that effectively converts an L-cysteine residue to S-glutathionyl-L-cysteine." [ChEBI:21264, DeltaMass:0, OMSSA:51, PubMed:3083866, PubMed:8344916, RESID:AA0229, Unimod:55]
-comment: From DeltaMass: Average Mass: 305
 comment: Glutamyl-transpeptidase cleaves glutathione into cysteinylglycine (Cys-Gly) and a Glu residue. [PubMed: 28537416]
 subset: PSI-MOD-slim
 synonym: "(2S)-2-amino-3-((2S)-2-((4R)-4-amino-4-carboxyl-1-oxobutyl)amino-3-(carboxylmethyl)amino-3-oxo-propyl)dithio-propanoic acid" EXACT RESID-systematic []
@@ -5879,9 +5878,9 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:55
 xref: uniprot.ptm:PTM-0311
-is_a: MOD:00905
-is_a: MOD:01862
-relationship: contains MOD:02026
+is_a: MOD:00905 ! modified L-cysteine residue
+is_a: MOD:01862 ! disulfide conjugated residue
+relationship: contains MOD:02026 ! S-(cysteinyl-glycyl)-L-cysteine
 
 [Term]
 id: MOD:00235
@@ -5906,8 +5905,8 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:275
 xref: uniprot.ptm:PTM-0280
-is_a: MOD:00905
-is_a: MOD:02077
+is_a: MOD:00905 ! modified L-cysteine residue
+is_a: MOD:02077 ! nitrosylated residue
 
 [Term]
 id: MOD:00236
@@ -5930,8 +5929,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:213
 xref: uniprot.ptm:PTM-0054
-is_a: MOD:00752
-is_a: MOD:00903
+is_a: MOD:00752 ! monoadenosine diphosphoribosyl (ADP-ribosyl) modified residue
+is_a: MOD:00903 ! modified L-asparagine residue
 
 [Term]
 id: MOD:00237
@@ -5960,8 +5959,8 @@ property_value: Origin "D" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:39
 xref: uniprot.ptm:PTM-0032
-is_a: MOD:00904
-is_a: MOD:01153
+is_a: MOD:00904 ! modified L-aspartic acid residue
+is_a: MOD:01153 ! methylthiolated residue
 
 [Term]
 id: MOD:00238
@@ -5984,9 +5983,9 @@ property_value: MassMono "303.121906" xsd:float
 property_value: Origin "K, Y" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0171
-is_a: MOD:00692
-is_a: MOD:02051
-is_a: MOD:02058
+is_a: MOD:00692 ! uncategorized crosslinked residues
+is_a: MOD:02051 ! crosslinked L-lysine residue
+is_a: MOD:02058 ! crosslinked L-tyrosine residue
 
 [Term]
 id: MOD:00239
@@ -6012,8 +6011,8 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:34
 xref: uniprot.ptm:PTM-0636
-is_a: MOD:00654
-is_a: MOD:01682
+is_a: MOD:00654 ! S-methylated residue
+is_a: MOD:01682 ! monomethylated L-cysteine
 
 [Term]
 id: MOD:00240
@@ -6036,7 +6035,7 @@ property_value: MassMono "144.089878" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: uniprot.ptm:PTM-0664
-is_a: MOD:01047
+is_a: MOD:01047 ! monohydroxylated lysine
 
 [Term]
 id: MOD:00241
@@ -6060,7 +6059,7 @@ property_value: MassMono "144.053492" xsd:float
 property_value: Origin "N" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:414
-is_a: MOD:00903
+is_a: MOD:00903 ! modified L-asparagine residue
 
 [Term]
 id: MOD:00242
@@ -6086,8 +6085,8 @@ property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:213
 xref: uniprot.ptm:PTM-0056
-is_a: MOD:00752
-is_a: MOD:00916
+is_a: MOD:00752 ! monoadenosine diphosphoribosyl (ADP-ribosyl) modified residue
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:00243
@@ -6107,9 +6106,9 @@ property_value: MassMono "170.014998" xsd:float
 property_value: Origin "C, S" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0376
-is_a: MOD:02044
-is_a: MOD:01421
-is_a: MOD:02082
+is_a: MOD:02044 ! crosslinked L-cysteine residue
+is_a: MOD:01421 ! oxazole/oxazoline ring crosslinked residues (Ser)
+is_a: MOD:02082 ! didehydrogenated and dehydrated residue
 
 [Term]
 id: MOD:00244
@@ -6129,9 +6128,9 @@ property_value: MassMono "172.030649" xsd:float
 property_value: Origin "C, S" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0381
-is_a: MOD:02044
-is_a: MOD:01421
-is_a: MOD:00954
+is_a: MOD:02044 ! crosslinked L-cysteine residue
+is_a: MOD:01421 ! oxazole/oxazoline ring crosslinked residues (Ser)
+is_a: MOD:00954 ! crosslinked residues with loss of water
 
 [Term]
 id: MOD:00245
@@ -6151,9 +6150,9 @@ property_value: MassMono "124.027277" xsd:float
 property_value: Origin "G, S" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0377
-is_a: MOD:02047
-is_a: MOD:01421
-is_a: MOD:02082
+is_a: MOD:02047 ! crosslinked glycine residue
+is_a: MOD:01421 ! oxazole/oxazoline ring crosslinked residues (Ser)
+is_a: MOD:02082 ! didehydrogenated and dehydrated residue
 
 [Term]
 id: MOD:00246
@@ -6173,9 +6172,9 @@ property_value: MassMono "140.004434" xsd:float
 property_value: Origin "C, G" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0378
-is_a: MOD:02047
-is_a: MOD:01420
-is_a: MOD:02082
+is_a: MOD:02047 ! crosslinked glycine residue
+is_a: MOD:01420 ! thiazole/thiazoline ring crosslinked residues
+is_a: MOD:02082 ! didehydrogenated and dehydrated residue
 
 [Term]
 id: MOD:00247
@@ -6195,9 +6194,9 @@ property_value: MassMono "170.014998" xsd:float
 property_value: Origin "C, S" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0363
-is_a: MOD:02055
-is_a: MOD:01420
-is_a: MOD:02082
+is_a: MOD:02055 ! crosslinked L-serine residue
+is_a: MOD:01420 ! thiazole/thiazoline ring crosslinked residues
+is_a: MOD:02082 ! didehydrogenated and dehydrated residue
 
 [Term]
 id: MOD:00248
@@ -6217,9 +6216,9 @@ property_value: MassMono "230.051384" xsd:float
 property_value: Origin "C, F" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0375
-is_a: MOD:02053
-is_a: MOD:01420
-is_a: MOD:02082
+is_a: MOD:02053 ! crosslinked L-phenylalanine residue
+is_a: MOD:01420 ! thiazole/thiazoline ring crosslinked residues
+is_a: MOD:02082 ! didehydrogenated and dehydrated residue
 
 [Term]
 id: MOD:00249
@@ -6239,8 +6238,8 @@ property_value: MassMono "185.992155" xsd:float
 property_value: Origin "C, C" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0360
-is_a: MOD:01420
-is_a: MOD:02082
+is_a: MOD:01420 ! thiazole/thiazoline ring crosslinked residues
+is_a: MOD:02082 ! didehydrogenated and dehydrated residue
 
 [Term]
 id: MOD:00250
@@ -6258,9 +6257,9 @@ property_value: MassAvg "211.28" xsd:float
 property_value: MassMono "211.077933" xsd:float
 property_value: Origin "C, K" xsd:string
 property_value: Source "hypothetical" xsd:string
-is_a: MOD:02051
-is_a: MOD:01420
-is_a: MOD:02082
+is_a: MOD:02051 ! crosslinked L-lysine residue
+is_a: MOD:01420 ! thiazole/thiazoline ring crosslinked residues
+is_a: MOD:02082 ! didehydrogenated and dehydrated residue
 
 [Term]
 id: MOD:00251
@@ -6275,8 +6274,8 @@ synonym: "O3-L-serine 5'-DNA phosphodiester" EXACT RESID-alternate []
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0226
-is_a: MOD:00750
-is_a: MOD:00916
+is_a: MOD:00750 ! deoxyribonucleic acid linked residue
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:00252
@@ -6287,7 +6286,7 @@ synonym: "keratosulfate" EXACT RESID-alternate []
 synonym: "poly[beta-1,4-(2-acetamido-2-deoxy-6-sulfate D-glucosyl)-beta-1,3-D-galactosyl]-beta-1,4-D-glucopyranuronosyl-beta-1,3-D-galactosyl-beta-1,3-D-galactosyl-beta-1,4-D-xylosyl-beta-1,3-L-threonine" EXACT RESID-systematic []
 property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00005
+is_a: MOD:00005 ! O-glycosyl-L-threonine
 
 [Term]
 id: MOD:00253
@@ -6302,8 +6301,8 @@ property_value: MassMono "1723.939410" xsd:float
 property_value: Origin "U" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:415
-is_a: MOD:00744
-is_a: MOD:01158
+is_a: MOD:00744 ! molybdenum pterin containing modification
+is_a: MOD:01158 ! modified L-selenocysteine residue
 
 [Term]
 id: MOD:00254
@@ -6316,8 +6315,8 @@ synonym: "O4'-L-tyrosine 5'-RNA phosphodiester" EXACT RESID-alternate []
 property_value: Origin "Y" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0229
-is_a: MOD:00751
-is_a: MOD:00919
+is_a: MOD:00751 ! ribonucleic acid linked residue
+is_a: MOD:00919 ! modified L-tyrosine residue
 
 [Term]
 id: MOD:00255
@@ -6341,9 +6340,9 @@ property_value: MassMono "298.106590" xsd:float
 property_value: Origin "H, Y" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0027
-is_a: MOD:00692
-is_a: MOD:02048
-is_a: MOD:02058
+is_a: MOD:00692 ! uncategorized crosslinked residues
+is_a: MOD:02048 ! crosslinked L-histidine residue
+is_a: MOD:02058 ! crosslinked L-tyrosine residue
 
 [Term]
 id: MOD:00256
@@ -6372,8 +6371,8 @@ property_value: Origin "M" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:425
 xref: uniprot.ptm:PTM-0175
-is_a: MOD:00709
-is_a: MOD:01855
+is_a: MOD:00709 ! sulfur oxygenated L-methionine
+is_a: MOD:01855 ! sulfur dioxygenated residue
 
 [Term]
 id: MOD:00257
@@ -6399,7 +6398,7 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:416
 xref: uniprot.ptm:PTM-0421
-is_a: MOD:00905
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00258
@@ -6421,8 +6420,8 @@ property_value: Origin "C, T" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0267
-is_a: MOD:00687
-is_a: MOD:02056
+is_a: MOD:00687 ! thioether crosslinked residues
+is_a: MOD:02056 ! crosslinked L-threonine residue
 
 [Term]
 id: MOD:00259
@@ -6436,8 +6435,8 @@ synonym: "O4'-L-tyrosine 5'-DNA phosphodiester" EXACT RESID-alternate []
 property_value: Origin "Y" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0228
-is_a: MOD:00750
-is_a: MOD:00919
+is_a: MOD:00750 ! deoxyribonucleic acid linked residue
+is_a: MOD:00919 ! modified L-tyrosine residue
 
 [Term]
 id: MOD:00260
@@ -6455,8 +6454,8 @@ property_value: MassAvg "180.08" xsd:float
 property_value: MassMono "180.006184" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00750
-is_a: MOD:00917
+is_a: MOD:00750 ! deoxyribonucleic acid linked residue
+is_a: MOD:00917 ! modified L-threonine residue
 
 [Term]
 id: MOD:00261
@@ -6484,8 +6483,8 @@ property_value: Origin "Y" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:417
 xref: uniprot.ptm:PTM-0333
-is_a: MOD:00919
-is_a: MOD:01166
+is_a: MOD:00919 ! modified L-tyrosine residue
+is_a: MOD:01166 ! uridylated residue
 
 [Term]
 id: MOD:00262
@@ -6505,8 +6504,8 @@ property_value: MassMono "292.105922" xsd:float
 property_value: Origin "E, Y" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
-is_a: MOD:02045
-is_a: MOD:00919
+is_a: MOD:02045 ! crosslinked L-glutamic acid residue
+is_a: MOD:00919 ! modified L-tyrosine residue
 
 [Term]
 id: MOD:00263
@@ -6533,8 +6532,8 @@ property_value: MassMono "689.288320" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:387
-is_a: MOD:00700
-is_a: MOD:00905
+is_a: MOD:00700 ! tetrapyrrole modified residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00264
@@ -6555,8 +6554,8 @@ property_value: MassAvg "792.97" xsd:float
 property_value: MassMono "792.297505" xsd:float
 property_value: Origin "C, C" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00700
-is_a: MOD:02044
+is_a: MOD:00700 ! tetrapyrrole modified residue
+is_a: MOD:02044 ! crosslinked L-cysteine residue
 
 [Term]
 id: MOD:00265
@@ -6577,8 +6576,8 @@ property_value: MassAvg "792.97" xsd:float
 property_value: MassMono "792.297505" xsd:float
 property_value: Origin "C, C" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00700
-is_a: MOD:02044
+is_a: MOD:00700 ! tetrapyrrole modified residue
+is_a: MOD:02044 ! crosslinked L-cysteine residue
 
 [Term]
 id: MOD:00266
@@ -6587,7 +6586,7 @@ def: "A protein modification that effectively forms a peptide bond between a C-t
 property_value: Origin "E" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
-is_a: MOD:00906
+is_a: MOD:00906 ! modified L-glutamic acid residue
 
 [Term]
 id: MOD:00267
@@ -6621,8 +6620,8 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:425
 xref: uniprot.ptm:PTM-0108
-is_a: MOD:00708
-is_a: MOD:01855
+is_a: MOD:00708 ! sulfur oxygenated L-cysteine
+is_a: MOD:01855 ! sulfur dioxygenated residue
 
 [Term]
 id: MOD:00268
@@ -6647,8 +6646,8 @@ property_value: Origin "Y" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:425
 xref: uniprot.ptm:PTM-0667
-is_a: MOD:00428
-is_a: MOD:00707
+is_a: MOD:00428 ! dihydroxylated residue
+is_a: MOD:00707 ! hydroxylated tyrosine
 
 [Term]
 id: MOD:00269
@@ -6675,7 +6674,7 @@ property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:419
 xref: uniprot.ptm:PTM-0230
-is_a: MOD:00916
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:00270
@@ -6702,7 +6701,7 @@ property_value: MassMono "72.998620" xsd:float
 property_value: Origin "G" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0004
-is_a: MOD:01625
+is_a: MOD:01625 ! 1-thioglycine
 
 [Term]
 id: MOD:00271
@@ -6721,9 +6720,9 @@ property_value: MassAvg "983.94" xsd:float
 property_value: MassMono "983.243341" xsd:float
 property_value: Origin "C, C, Y" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00699
-is_a: MOD:02067
-is_a: MOD:02075
+is_a: MOD:00699 ! porphyrin modified residue
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
+is_a: MOD:02075 ! metal or metal cluster coordinated L-tyrosine residue
 
 [Term]
 id: MOD:00272
@@ -6752,8 +6751,8 @@ property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:405
 xref: uniprot.ptm:PTM-0393
-is_a: MOD:00917
-is_a: MOD:01165
+is_a: MOD:00917 ! modified L-threonine residue
+is_a: MOD:01165 ! adenylated residue
 
 [Term]
 id: MOD:00273
@@ -6776,10 +6775,10 @@ property_value: MassAvg "1168.43" xsd:float
 property_value: MassMono "1167.766769" xsd:float
 property_value: Origin "C, C, C, C, E, E, H" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00739
-is_a: MOD:02067
-is_a: MOD:02068
-is_a: MOD:02070
+is_a: MOD:00739 ! iron-sulfur cluster containing modification
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
+is_a: MOD:02068 ! metal or metal cluster coordinated L-glutamic acid residue
+is_a: MOD:02070 ! metal or metal cluster coordinated L-histidine residue
 
 [Term]
 id: MOD:00274
@@ -6811,8 +6810,8 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:421
 xref: uniprot.ptm:PTM-0106
-is_a: MOD:00905
-is_a: MOD:01886
+is_a: MOD:00905 ! modified L-cysteine residue
+is_a: MOD:01886 ! thiolated residue
 
 [Term]
 id: MOD:00275
@@ -6836,9 +6835,9 @@ property_value: MassMono "298.106590" xsd:float
 property_value: Origin "H, Y" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0003
-is_a: MOD:00692
-is_a: MOD:02048
-is_a: MOD:02058
+is_a: MOD:00692 ! uncategorized crosslinked residues
+is_a: MOD:02048 ! crosslinked L-histidine residue
+is_a: MOD:02058 ! crosslinked L-tyrosine residue
 
 [Term]
 id: MOD:00276
@@ -6857,9 +6856,9 @@ property_value: MassAvg "948.94" xsd:float
 property_value: MassMono "948.274976" xsd:float
 property_value: Origin "C, C, K" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00699
-is_a: MOD:02067
-is_a: MOD:02074
+is_a: MOD:00699 ! porphyrin modified residue
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
+is_a: MOD:02074 ! metal or metal cluster coordinated L-lysine residue
 
 [Term]
 id: MOD:00277
@@ -6884,8 +6883,8 @@ property_value: MassMono "170.116761" xsd:float
 property_value: Origin "R" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0050
-is_a: MOD:00414
-is_a: MOD:00656
+is_a: MOD:00414 ! monomethylated L-arginine
+is_a: MOD:00656 ! C-methylated residue
 
 [Term]
 id: MOD:00278
@@ -6909,8 +6908,8 @@ property_value: MassMono "142.074228" xsd:float
 property_value: Origin "Q" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0016
-is_a: MOD:00656
-is_a: MOD:00722
+is_a: MOD:00656 ! C-methylated residue
+is_a: MOD:00722 ! monomethylated L-glutamine
 
 [Term]
 id: MOD:00279
@@ -6933,8 +6932,8 @@ property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:422
 xref: uniprot.ptm:PTM-0224
-is_a: MOD:00905
-is_a: MOD:01170
+is_a: MOD:00905 ! modified L-cysteine residue
+is_a: MOD:01170 ! pyruvic acid iminylated residue
 
 [Term]
 id: MOD:00280
@@ -6957,8 +6956,8 @@ property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:422
 xref: uniprot.ptm:PTM-0225
-is_a: MOD:00920
-is_a: MOD:01170
+is_a: MOD:00920 ! modified L-valine residue
+is_a: MOD:01170 ! pyruvic acid iminylated residue
 
 [Term]
 id: MOD:00281
@@ -6980,8 +6979,8 @@ property_value: MassAvg "753.64" xsd:float
 property_value: MassMono "753.236205" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00699
-is_a: MOD:02070
+is_a: MOD:00699 ! porphyrin modified residue
+is_a: MOD:02070 ! metal or metal cluster coordinated L-histidine residue
 
 [Term]
 id: MOD:00282
@@ -7009,9 +7008,9 @@ property_value: Origin "C" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: Unimod:423
 xref: uniprot.ptm:PTM-0282
-is_a: MOD:00745
-is_a: MOD:00778
-is_a: MOD:00905
+is_a: MOD:00745 ! selenium containing residue
+is_a: MOD:00778 ! residues isobaric at 182.9-183.0 Da
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00283
@@ -7026,7 +7025,7 @@ synonym: "silaffin polycationic lysine derivative" EXACT RESID-alternate []
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0198
-is_a: MOD:00912
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:00284
@@ -7046,9 +7045,9 @@ property_value: MassAvg "856.67" xsd:float
 property_value: MassMono "856.215529" xsd:float
 property_value: Origin "D, E" xsd:string
 property_value: Source "hypothetical" xsd:string
-is_a: MOD:00699
-is_a: MOD:02066
-is_a: MOD:02068
+is_a: MOD:00699 ! porphyrin modified residue
+is_a: MOD:02066 ! metal or metal cluster coordinated L-aspartic acid residue
+is_a: MOD:02068 ! metal or metal cluster coordinated L-glutamic acid residue
 
 [Term]
 id: MOD:00285
@@ -7069,10 +7068,10 @@ property_value: MassAvg "988.87" xsd:float
 property_value: MassMono "988.263290" xsd:float
 property_value: Origin "D, E, M" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00699
-is_a: MOD:02066
-is_a: MOD:02068
-is_a: MOD:02071
+is_a: MOD:00699 ! porphyrin modified residue
+is_a: MOD:02066 ! metal or metal cluster coordinated L-aspartic acid residue
+is_a: MOD:02068 ! metal or metal cluster coordinated L-glutamic acid residue
+is_a: MOD:02071 ! metal or metal cluster coordinated L-methionine residue
 
 [Term]
 id: MOD:00286
@@ -7092,8 +7091,8 @@ property_value: MassMono "1675.994960" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: Unimod:424
-is_a: MOD:02067
-is_a: MOD:01167
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
+is_a: MOD:01167 ! molybdopterin guanine dinucleotide
 
 [Term]
 id: MOD:00287
@@ -7121,7 +7120,7 @@ property_value: Origin "P" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:425
 xref: uniprot.ptm:PTM-0306
-is_a: MOD:00866
+is_a: MOD:00866 ! dihydroxylated proline
 
 [Term]
 id: MOD:00288
@@ -7144,9 +7143,9 @@ property_value: MassMono "330.012415" xsd:float
 property_value: Origin "E, Y" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0263
-is_a: MOD:00692
-is_a: MOD:02045
-is_a: MOD:02058
+is_a: MOD:00692 ! uncategorized crosslinked residues
+is_a: MOD:02045 ! crosslinked L-glutamic acid residue
+is_a: MOD:02058 ! crosslinked L-tyrosine residue
 
 [Term]
 id: MOD:00289
@@ -7166,9 +7165,9 @@ property_value: MassAvg "794.15" xsd:float
 property_value: MassMono "793.684297" xsd:float
 property_value: Origin "C, C, C, H" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00739
-is_a: MOD:02067
-is_a: MOD:02070
+is_a: MOD:00739 ! iron-sulfur cluster containing modification
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
+is_a: MOD:02070 ! metal or metal cluster coordinated L-histidine residue
 
 [Term]
 id: MOD:00290
@@ -7188,9 +7187,9 @@ property_value: MassAvg "794.15" xsd:float
 property_value: MassMono "793.684297" xsd:float
 property_value: Origin "C, C, C, H" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00739
-is_a: MOD:02067
-is_a: MOD:02070
+is_a: MOD:00739 ! iron-sulfur cluster containing modification
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
+is_a: MOD:02070 ! metal or metal cluster coordinated L-histidine residue
 
 [Term]
 id: MOD:00291
@@ -7209,9 +7208,9 @@ property_value: MassAvg "772.09" xsd:float
 property_value: MassMono "771.652328" xsd:float
 property_value: Origin "C, C, C, D" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00739
-is_a: MOD:02066
-is_a: MOD:02067
+is_a: MOD:00739 ! iron-sulfur cluster containing modification
+is_a: MOD:02066 ! metal or metal cluster coordinated L-aspartic acid residue
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
 
 [Term]
 id: MOD:00292
@@ -7231,8 +7230,8 @@ property_value: MassMono "198.100442" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:422
-is_a: MOD:00912
-is_a: MOD:01170
+is_a: MOD:00912 ! modified L-lysine residue
+is_a: MOD:01170 ! pyruvic acid iminylated residue
 
 [Term]
 id: MOD:00293
@@ -7250,9 +7249,9 @@ property_value: MassAvg "744.08" xsd:float
 property_value: MassMono "743.657414" xsd:float
 property_value: Origin "C, C, C, S" xsd:string
 property_value: Source "hypothetical" xsd:string
-is_a: MOD:00739
-is_a: MOD:02067
-is_a: MOD:02072
+is_a: MOD:00739 ! iron-sulfur cluster containing modification
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
+is_a: MOD:02072 ! metal or metal cluster coordinated L-serine residue
 
 [Term]
 id: MOD:00294
@@ -7272,10 +7271,10 @@ property_value: MassAvg "778.09" xsd:float
 property_value: MassMono "777.707141" xsd:float
 property_value: Origin "C, C, H, S" xsd:string
 property_value: Source "hypothetical" xsd:string
-is_a: MOD:00739
-is_a: MOD:02067
-is_a: MOD:02070
-is_a: MOD:02072
+is_a: MOD:00739 ! iron-sulfur cluster containing modification
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
+is_a: MOD:02070 ! metal or metal cluster coordinated L-histidine residue
+is_a: MOD:02072 ! metal or metal cluster coordinated L-serine residue
 
 [Term]
 id: MOD:00295
@@ -7301,8 +7300,8 @@ property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:426
 xref: uniprot.ptm:PTM-0239
-is_a: MOD:00669
-is_a: MOD:02003
+is_a: MOD:00669 ! O-octanoylated residue
+is_a: MOD:02003 ! O3-acylated L-serine
 
 [Term]
 id: MOD:00296
@@ -7325,8 +7324,8 @@ property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:54
 xref: uniprot.ptm:PTM-0577
-is_a: MOD:00447
-is_a: MOD:00916
+is_a: MOD:00447 ! N-glucuronylated residue
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:00297
@@ -7346,11 +7345,11 @@ property_value: MassAvg "1171.28" xsd:float
 property_value: MassMono "1169.767174" xsd:float
 property_value: Origin "C, C, C, C, E, E, H" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00739
-is_a: MOD:00741
-is_a: MOD:02067
-is_a: MOD:02068
-is_a: MOD:02070
+is_a: MOD:00739 ! iron-sulfur cluster containing modification
+is_a: MOD:00741 ! nickel containing modified residue
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
+is_a: MOD:02068 ! metal or metal cluster coordinated L-glutamic acid residue
+is_a: MOD:02070 ! metal or metal cluster coordinated L-histidine residue
 
 [Term]
 id: MOD:00298
@@ -7370,12 +7369,12 @@ property_value: MassAvg "1129.24" xsd:float
 property_value: MassMono "1127.756609" xsd:float
 property_value: Origin "C, C, C, C, E, H, S" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00739
-is_a: MOD:00741
-is_a: MOD:02067
-is_a: MOD:02068
-is_a: MOD:02070
-is_a: MOD:02072
+is_a: MOD:00739 ! iron-sulfur cluster containing modification
+is_a: MOD:00741 ! nickel containing modified residue
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
+is_a: MOD:02068 ! metal or metal cluster coordinated L-glutamic acid residue
+is_a: MOD:02070 ! metal or metal cluster coordinated L-histidine residue
+is_a: MOD:02072 ! metal or metal cluster coordinated L-serine residue
 
 [Term]
 id: MOD:00299
@@ -7399,9 +7398,9 @@ property_value: MassMono "225.111341" xsd:float
 property_value: Origin "K, N" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0153
-is_a: MOD:02042
-is_a: MOD:00946
-is_a: MOD:01929
+is_a: MOD:02042 ! crosslinked L-asparagine residue
+is_a: MOD:00946 ! crosslinked residues with loss of ammonia
+is_a: MOD:01929 ! N6-(L-isoaspartyl)-L-lysine
 
 [Term]
 id: MOD:00300
@@ -7417,8 +7416,8 @@ synonym: "O-ADP-ribosylation (on Glutamate or C terminus)" EXACT DeltaMass-label
 property_value: Origin "E" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:213
-is_a: MOD:02087
-is_a: MOD:00906
+is_a: MOD:02087 ! adenosine diphosphoribosyl (ADP-ribosyl) modified residue
+is_a: MOD:00906 ! modified L-glutamic acid residue
 
 [Term]
 id: MOD:00301
@@ -7443,8 +7442,8 @@ property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:428
 xref: uniprot.ptm:PTM-0586
-is_a: MOD:00916
-is_a: MOD:01804
+is_a: MOD:00916 ! modified L-serine residue
+is_a: MOD:01804 ! glycosylphosphorylated residue
 
 [Term]
 id: MOD:00302
@@ -7468,8 +7467,8 @@ property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:429
 xref: uniprot.ptm:PTM-0594
-is_a: MOD:00916
-is_a: MOD:01804
+is_a: MOD:00916 ! modified L-serine residue
+is_a: MOD:01804 ! glycosylphosphorylated residue
 
 [Term]
 id: MOD:00303
@@ -7488,9 +7487,9 @@ property_value: MassAvg "1256.19" xsd:float
 property_value: MassMono "1253.050808" xsd:float
 property_value: Origin "H, H, H, H, H, H, H" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00742
-is_a: MOD:00860
-is_a: MOD:02070
+is_a: MOD:00742 ! copper containing modified residue
+is_a: MOD:00860 ! sulfur containing modified residue
+is_a: MOD:02070 ! metal or metal cluster coordinated L-histidine residue
 
 [Term]
 id: MOD:00304
@@ -7519,9 +7518,9 @@ property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: Unimod:34
 xref: uniprot.ptm:PTM-0167
-is_a: MOD:00599
-is_a: MOD:00662
-is_a: MOD:01689
+is_a: MOD:00599 ! monomethylated residue
+is_a: MOD:00662 ! methylated leucine
+is_a: MOD:01689 ! alpha-carboxyl methylated residue
 
 [Term]
 id: MOD:00305
@@ -7541,9 +7540,9 @@ property_value: MassAvg "1369.03" xsd:float
 property_value: MassMono "1368.310179" xsd:float
 property_value: Origin "C, C, C, C, C, C, S" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00739
-is_a: MOD:02067
-is_a: MOD:02072
+is_a: MOD:00739 ! iron-sulfur cluster containing modification
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
+is_a: MOD:02072 ! metal or metal cluster coordinated L-serine residue
 
 [Term]
 id: MOD:00306
@@ -7559,8 +7558,8 @@ property_value: Formula "C 6 H 11 N 1 O 1" xsd:string
 property_value: MassAvg "113.16" xsd:float
 property_value: MassMono "113.084064" xsd:float
 property_value: Origin "X" xsd:string
-is_a: MOD:00569
-is_a: MOD:00624
+is_a: MOD:00569 ! residues isobaric at a resolution below 0.000001 Da
+is_a: MOD:00624 ! residues isobaric at 113.0-113.1 Da
 
 [Term]
 id: MOD:00307
@@ -7588,9 +7587,9 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: Unimod:23
-is_a: MOD:00601
-is_a: MOD:00704
-is_a: MOD:00903
+is_a: MOD:00601 ! cyclized residue
+is_a: MOD:00704 ! dehydrated residue
+is_a: MOD:00903 ! modified L-asparagine residue
 
 [Term]
 id: MOD:00308
@@ -7613,9 +7612,9 @@ property_value: Origin "Q" xsd:string
 property_value: Source "hypothetical" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: Unimod:23
-is_a: MOD:00601
-is_a: MOD:00704
-is_a: MOD:00907
+is_a: MOD:00601 ! cyclized residue
+is_a: MOD:00704 ! dehydrated residue
+is_a: MOD:00907 ! modified L-glutamine residue
 
 [Term]
 id: MOD:00309
@@ -7641,8 +7640,8 @@ property_value: MassMono "159.016772" xsd:float
 property_value: Origin "D" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: Unimod:299
-is_a: MOD:00904
-is_a: MOD:01152
+is_a: MOD:00904 ! modified L-aspartic acid residue
+is_a: MOD:01152 ! carboxylated residue
 
 [Term]
 id: MOD:00310
@@ -7666,8 +7665,8 @@ property_value: MassMono "170.116761" xsd:float
 property_value: Origin "R" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: uniprot.ptm:PTM-0185
-is_a: MOD:00414
-is_a: MOD:00602
+is_a: MOD:00414 ! monomethylated L-arginine
+is_a: MOD:00602 ! N-methylated residue
 
 [Term]
 id: MOD:00311
@@ -7689,9 +7688,9 @@ property_value: MassMono "868.108744" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: Unimod:281
-is_a: MOD:00861
-is_a: MOD:00905
-is_a: MOD:01862
+is_a: MOD:00861 ! phosphorus containing modified residue
+is_a: MOD:00905 ! modified L-cysteine residue
+is_a: MOD:01862 ! disulfide conjugated residue
 
 [Term]
 id: MOD:00312
@@ -7715,8 +7714,8 @@ property_value: MassMono "313.207550" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: Unimod:45
-is_a: MOD:00655
-is_a: MOD:00905
+is_a: MOD:00655 ! S-myristoylated residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00313
@@ -7740,8 +7739,8 @@ property_value: Origin "C" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: Unimod:431
 xref: uniprot.ptm:PTM-0645
-is_a: MOD:02002
-is_a: MOD:00905
+is_a: MOD:02002 ! S-palmitoleylated residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00314
@@ -7767,8 +7766,8 @@ property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: Unimod:432
 xref: uniprot.ptm:PTM-0090
-is_a: MOD:00908
-is_a: MOD:01155
+is_a: MOD:00908 ! modified glycine residue
+is_a: MOD:01155 ! lipoconjugated residue
 
 [Term]
 id: MOD:00315
@@ -7789,10 +7788,10 @@ property_value: MassAvg "1089.16" xsd:float
 property_value: MassMono "1087.593333" xsd:float
 property_value: Origin "C, C, C, C, C, H" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00739
-is_a: MOD:00741
-is_a: MOD:02067
-is_a: MOD:02070
+is_a: MOD:00739 ! iron-sulfur cluster containing modification
+is_a: MOD:00741 ! nickel containing modified residue
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
+is_a: MOD:02070 ! metal or metal cluster coordinated L-histidine residue
 
 [Term]
 id: MOD:00316
@@ -7818,9 +7817,9 @@ property_value: Origin "N" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: Unimod:36
 xref: uniprot.ptm:PTM-0182
-is_a: MOD:00429
-is_a: MOD:00602
-is_a: MOD:00673
+is_a: MOD:00429 ! dimethylated residue
+is_a: MOD:00602 ! N-methylated residue
+is_a: MOD:00673 ! methylated asparagine
 
 [Term]
 id: MOD:00317
@@ -7841,7 +7840,7 @@ property_value: MassMono "392.282764" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:433
-is_a: MOD:00912
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:00318
@@ -7864,8 +7863,8 @@ property_value: MassMono "317.047027" xsd:float
 property_value: Origin "C, W" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0041
-is_a: MOD:00687
-is_a: MOD:02057
+is_a: MOD:00687 ! thioether crosslinked residues
+is_a: MOD:02057 ! crosslinked L-tryptophan residue
 
 [Term]
 id: MOD:00319
@@ -7886,8 +7885,8 @@ property_value: MassMono "216.020478" xsd:float
 property_value: Origin "C, D" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0025
-is_a: MOD:02043
-is_a: MOD:01993
+is_a: MOD:02043 ! crosslinked L-aspartic acid residue
+is_a: MOD:01993 ! beta-carbon thioether crosslinked residues
 
 [Term]
 id: MOD:00320
@@ -7907,8 +7906,8 @@ property_value: MassMono "230.036128" xsd:float
 property_value: Origin "C, E" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0040
-is_a: MOD:00687
-is_a: MOD:02045
+is_a: MOD:00687 ! thioether crosslinked residues
+is_a: MOD:02045 ! crosslinked L-glutamic acid residue
 
 [Term]
 id: MOD:00321
@@ -7930,8 +7929,8 @@ property_value: Origin "D" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:434
 xref: uniprot.ptm:PTM-0091
-is_a: MOD:00904
-is_a: MOD:01155
+is_a: MOD:00904 ! modified L-aspartic acid residue
+is_a: MOD:01155 ! lipoconjugated residue
 
 [Term]
 id: MOD:00322
@@ -7959,8 +7958,8 @@ property_value: MassMono "151.074562" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0290
-is_a: MOD:02038
-is_a: MOD:00724
+is_a: MOD:02038 ! monomethylated L-histidine
+is_a: MOD:00724 ! N-methylated L-histidine
 
 [Term]
 id: MOD:00323
@@ -7988,8 +7987,8 @@ property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: Unimod:34
 xref: uniprot.ptm:PTM-0170
-is_a: MOD:01683
-is_a: MOD:01689
+is_a: MOD:01683 ! monomethylated L-lysine
+is_a: MOD:01689 ! alpha-carboxyl methylated residue
 
 [Term]
 id: MOD:00324
@@ -8006,8 +8005,8 @@ property_value: MassAvg "1675.09" xsd:float
 property_value: MassMono "1676.012718" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00744
-is_a: MOD:02072
+is_a: MOD:00744 ! molybdenum pterin containing modification
+is_a: MOD:02072 ! metal or metal cluster coordinated L-serine residue
 
 [Term]
 id: MOD:00325
@@ -8030,8 +8029,8 @@ property_value: MassMono "160.030649" xsd:float
 property_value: Origin "N" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: Unimod:39
-is_a: MOD:00903
-is_a: MOD:01153
+is_a: MOD:00903 ! modified L-asparagine residue
+is_a: MOD:01153 ! methylthiolated residue
 
 [Term]
 id: MOD:00326
@@ -8056,7 +8055,7 @@ property_value: MassMono "237.147727" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:435
-is_a: MOD:00912
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:00327
@@ -8078,7 +8077,7 @@ property_value: MassMono "202.074228" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: uniprot.ptm:PTM-0031
-is_a: MOD:01622
+is_a: MOD:01622 ! monohydroxylated tryptophan
 
 [Term]
 id: MOD:00328
@@ -8090,8 +8089,8 @@ synonym: "O4'-(phospho-3'-DNA)-L-tyrosine" EXACT RESID-name []
 synonym: "O4'-L-tyrosine 3'-DNA phosphodiester" EXACT RESID-alternate []
 property_value: Origin "Y" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00750
-is_a: MOD:00919
+is_a: MOD:00750 ! deoxyribonucleic acid linked residue
+is_a: MOD:00919 ! modified L-tyrosine residue
 
 [Term]
 id: MOD:00329
@@ -8113,8 +8112,8 @@ property_value: MassMono "743.204236" xsd:float
 property_value: Origin "E" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:436
-is_a: MOD:00699
-is_a: MOD:02068
+is_a: MOD:00699 ! porphyrin modified residue
+is_a: MOD:02068 ! metal or metal cluster coordinated L-glutamic acid residue
 
 [Term]
 id: MOD:00330
@@ -8139,8 +8138,8 @@ property_value: MassMono "482.106346" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:413
-is_a: MOD:00909
-is_a: MOD:01163
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:01163 ! guanylated residue
 
 [Term]
 id: MOD:00331
@@ -8162,8 +8161,8 @@ property_value: MassAvg "704.30" xsd:float
 property_value: MassMono "703.700181" xsd:float
 property_value: Origin "C, C, C, C" xsd:string
 property_value: Source "hypothetical" xsd:string
-is_a: MOD:00739
-is_a: MOD:02067
+is_a: MOD:00739 ! iron-sulfur cluster containing modification
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
 
 [Term]
 id: MOD:00332
@@ -8187,8 +8186,8 @@ property_value: Origin "R" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:41
 xref: uniprot.ptm:PTM-0515
-is_a: MOD:00433
-is_a: MOD:01980
+is_a: MOD:00433 ! monoglucosylated residue
+is_a: MOD:01980 ! omega-N-glycosyl-L-arginine
 
 [Term]
 id: MOD:00333
@@ -8214,8 +8213,8 @@ property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: Unimod:437
 xref: uniprot.ptm:PTM-0335
-is_a: MOD:00701
-is_a: MOD:00903
+is_a: MOD:00701 ! nucleotide or nucleic acid modified residue
+is_a: MOD:00903 ! modified L-asparagine residue
 
 [Term]
 id: MOD:00334
@@ -8240,8 +8239,8 @@ property_value: MassMono "753.236205" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: Unimod:390
-is_a: MOD:00699
-is_a: MOD:02070
+is_a: MOD:00699 ! porphyrin modified residue
+is_a: MOD:02070 ! metal or metal cluster coordinated L-histidine residue
 
 [Term]
 id: MOD:00335
@@ -8263,9 +8262,9 @@ property_value: MassMono "202.041213" xsd:float
 property_value: Origin "C, T" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0069
-is_a: MOD:02056
-is_a: MOD:01993
-relationship: has_functional_parent MOD:01981
+is_a: MOD:02056 ! crosslinked L-threonine residue
+is_a: MOD:01993 ! beta-carbon thioether crosslinked residues
+relationship: has_functional_parent MOD:01981 ! 3-methyllanthionine
 
 [Term]
 id: MOD:00336
@@ -8284,9 +8283,9 @@ property_value: MassAvg "596.28" xsd:float
 property_value: MassMono "595.838311" xsd:float
 property_value: Origin "C, C, C, D" xsd:string
 property_value: Source "hypothetical" xsd:string
-is_a: MOD:00739
-is_a: MOD:02066
-is_a: MOD:02067
+is_a: MOD:00739 ! iron-sulfur cluster containing modification
+is_a: MOD:02066 ! metal or metal cluster coordinated L-aspartic acid residue
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
 
 [Term]
 id: MOD:00337
@@ -8314,8 +8313,8 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:5
 xref: uniprot.ptm:PTM-0649
-is_a: MOD:00398
-is_a: MOD:00905
+is_a: MOD:00398 ! carbamoylated residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00338
@@ -8340,8 +8339,8 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:438
 xref: uniprot.ptm:PTM-0650
-is_a: MOD:00893
-is_a: MOD:00905
+is_a: MOD:00893 ! residues isobaric at 128.0-128.1
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00339
@@ -8363,8 +8362,8 @@ property_value: MassMono "445.796098" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:439
-is_a: MOD:00738
-is_a: MOD:02067
+is_a: MOD:00738 ! iron containing modified residue
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
 
 [Term]
 id: MOD:00340
@@ -8390,7 +8389,7 @@ property_value: MassMono "145.030983" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:440
-is_a: MOD:00905
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00341
@@ -8414,8 +8413,8 @@ property_value: MassMono "127.099714" xsd:float
 property_value: Origin "I" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: uniprot.ptm:PTM-0215
-is_a: MOD:00715
-is_a: MOD:01680
+is_a: MOD:00715 ! methylated isoleucine
+is_a: MOD:01680 ! alpha-amino monomethylated residue
 
 [Term]
 id: MOD:00342
@@ -8440,8 +8439,8 @@ property_value: MassMono "127.099714" xsd:float
 property_value: Origin "L" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: uniprot.ptm:PTM-0216
-is_a: MOD:01680
-is_a: MOD:01808
+is_a: MOD:01680 ! alpha-amino monomethylated residue
+is_a: MOD:01808 ! N-methylated leucine
 
 [Term]
 id: MOD:00343
@@ -8465,8 +8464,8 @@ property_value: MassMono "177.078979" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: uniprot.ptm:PTM-0220
-is_a: MOD:00718
-is_a: MOD:01680
+is_a: MOD:00718 ! methylated tyrosine
+is_a: MOD:01680 ! alpha-amino monomethylated residue
 
 [Term]
 id: MOD:00344
@@ -8493,8 +8492,8 @@ property_value: Origin "G" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0223
-is_a: MOD:00908
-is_a: MOD:01685
+is_a: MOD:00908 ! modified glycine residue
+is_a: MOD:01685 ! alpha-amino palmitoylated residue
 
 [Term]
 id: MOD:00345
@@ -8515,8 +8514,8 @@ property_value: MassMono "248.061949" xsd:float
 property_value: Origin "C, F" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0012
-is_a: MOD:02053
-is_a: MOD:01992
+is_a: MOD:02053 ! crosslinked L-phenylalanine residue
+is_a: MOD:01992 ! alpha-carbon thioether crosslinked residues
 
 [Term]
 id: MOD:00346
@@ -8537,9 +8536,9 @@ property_value: MassMono "248.061949" xsd:float
 property_value: Origin "C, F" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0011
-is_a: MOD:00664
-is_a: MOD:02053
-is_a: MOD:01992
+is_a: MOD:00664 ! stereoisomerized residue
+is_a: MOD:02053 ! crosslinked L-phenylalanine residue
+is_a: MOD:01992 ! alpha-carbon thioether crosslinked residues
 
 [Term]
 id: MOD:00347
@@ -8560,9 +8559,9 @@ property_value: MassMono "202.041213" xsd:float
 property_value: Origin "C, T" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0010
-is_a: MOD:00664
-is_a: MOD:02056
-is_a: MOD:01992
+is_a: MOD:00664 ! stereoisomerized residue
+is_a: MOD:02056 ! crosslinked L-threonine residue
+is_a: MOD:01992 ! alpha-carbon thioether crosslinked residues
 
 [Term]
 id: MOD:00348
@@ -8584,8 +8583,8 @@ property_value: Origin "A" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0374
-is_a: MOD:00901
-is_a: MOD:01679
+is_a: MOD:00901 ! modified L-alanine residue
+is_a: MOD:01679 ! alpha-aminocarbamoylated residue
 
 [Term]
 id: MOD:00349
@@ -8608,9 +8607,9 @@ property_value: MassMono "188.025563" xsd:float
 property_value: Origin "C, S" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0037
-is_a: MOD:02044
-is_a: MOD:02055
-is_a: MOD:01861
+is_a: MOD:02044 ! crosslinked L-cysteine residue
+is_a: MOD:02055 ! crosslinked L-serine residue
+is_a: MOD:01861 ! isothiazolidinone ring crosslinked residues
 
 [Term]
 id: MOD:00350
@@ -8623,8 +8622,8 @@ property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0246
-is_a: MOD:00917
-is_a: MOD:01159
+is_a: MOD:00917 ! modified L-threonine residue
+is_a: MOD:01159 ! peptidoglycanated residue
 
 [Term]
 id: MOD:00351
@@ -8644,8 +8643,8 @@ property_value: Origin "G" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0249
-is_a: MOD:00908
-is_a: MOD:01155
+is_a: MOD:00908 ! modified glycine residue
+is_a: MOD:01155 ! lipoconjugated residue
 
 [Term]
 id: MOD:00352
@@ -8664,8 +8663,8 @@ property_value: MassMono "888.789439" xsd:float
 property_value: Origin "Q" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0236
-is_a: MOD:00907
-is_a: MOD:01155
+is_a: MOD:00907 ! modified L-glutamine residue
+is_a: MOD:01155 ! lipoconjugated residue
 
 [Term]
 id: MOD:00353
@@ -8684,10 +8683,10 @@ property_value: MassMono "477.159103" xsd:float
 property_value: Origin "M, W, Y" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0328
-is_a: MOD:00692
-is_a: MOD:02052
-is_a: MOD:02057
-is_a: MOD:02058
+is_a: MOD:00692 ! uncategorized crosslinked residues
+is_a: MOD:02052 ! crosslinked L-methionine residue
+is_a: MOD:02057 ! crosslinked L-tryptophan residue
+is_a: MOD:02058 ! crosslinked L-tyrosine residue
 
 [Term]
 id: MOD:00354
@@ -8712,8 +8711,8 @@ property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:442
 xref: uniprot.ptm:PTM-0126
-is_a: MOD:00917
-is_a: MOD:01164
+is_a: MOD:00917 ! modified L-threonine residue
+is_a: MOD:01164 ! riboflavin-phosphorylated residue
 
 [Term]
 id: MOD:00355
@@ -8738,8 +8737,8 @@ property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:442
 xref: uniprot.ptm:PTM-0125
-is_a: MOD:00916
-is_a: MOD:01164
+is_a: MOD:00916 ! modified L-serine residue
+is_a: MOD:01164 ! riboflavin-phosphorylated residue
 
 [Term]
 id: MOD:00356
@@ -8764,8 +8763,8 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:443
 xref: uniprot.ptm:PTM-0270
-is_a: MOD:02083
-is_a: MOD:00905
+is_a: MOD:02083 ! 4alpha-FMN modified residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00357
@@ -8792,8 +8791,8 @@ property_value: Origin "H" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:409
 xref: uniprot.ptm:PTM-0289
-is_a: MOD:02085
-is_a: MOD:00909
+is_a: MOD:02085 ! 8alpha-FMN modified residue
+is_a: MOD:00909 ! modified L-histidine residue
 
 [Term]
 id: MOD:00358
@@ -8819,8 +8818,8 @@ property_value: MassMono "591.147877" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: Unimod:409
-is_a: MOD:02085
-is_a: MOD:00909
+is_a: MOD:02085 ! 8alpha-FMN modified residue
+is_a: MOD:00909 ! modified L-histidine residue
 
 [Term]
 id: MOD:00359
@@ -8846,8 +8845,8 @@ property_value: Origin "R" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0180
-is_a: MOD:00902
-is_a: MOD:01458
+is_a: MOD:00902 ! modified L-arginine residue
+is_a: MOD:01458 ! alpha-amino acetylated residue
 
 [Term]
 id: MOD:00360
@@ -8867,10 +8866,10 @@ property_value: MassMono "1025.844039" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:444
-is_a: MOD:00742
-is_a: MOD:00744
-is_a: MOD:00860
-is_a: MOD:02067
+is_a: MOD:00742 ! copper containing modified residue
+is_a: MOD:00744 ! molybdenum pterin containing modification
+is_a: MOD:00860 ! sulfur containing modified residue
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
 
 [Term]
 id: MOD:00361
@@ -8889,8 +8888,8 @@ property_value: MassAvg "1056.45" xsd:float
 property_value: MassMono "1055.769901" xsd:float
 property_value: Origin "C, C, C" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00739
-is_a: MOD:02067
+is_a: MOD:00739 ! iron-sulfur cluster containing modification
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
 
 [Term]
 id: MOD:00362
@@ -8909,9 +8908,9 @@ property_value: MassAvg "638.39" xsd:float
 property_value: MassMono "637.920304" xsd:float
 property_value: Origin "C, C, C, R" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00739
-is_a: MOD:02076
-is_a: MOD:02067
+is_a: MOD:00739 ! iron-sulfur cluster containing modification
+is_a: MOD:02076 ! metal or metal cluster coordinated L-arginine residue
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
 
 [Term]
 id: MOD:00363
@@ -8932,8 +8931,8 @@ property_value: MassMono "251.947170" xsd:float
 property_value: Origin "C, U" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0109
-is_a: MOD:02061
-is_a: MOD:01627
+is_a: MOD:02061 ! crosslinked L-selenocysteine residue
+is_a: MOD:01627 ! L-cysteinyl-L-selenocysteine
 
 [Term]
 id: MOD:00364
@@ -8966,10 +8965,10 @@ property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:445
 xref: uniprot.ptm:PTM-0186
-is_a: MOD:00602
-is_a: MOD:00912
-relationship: has_functional_parent MOD:00037
-relationship: has_functional_parent MOD:00083
+is_a: MOD:00602 ! N-methylated residue
+is_a: MOD:00912 ! modified L-lysine residue
+relationship: has_functional_parent MOD:00037 ! 5-hydroxy-L-lysine
+relationship: has_functional_parent MOD:00083 ! N6,N6,N6-trimethyl-L-lysine
 
 [Term]
 id: MOD:00365
@@ -8992,10 +8991,10 @@ property_value: Origin "E, G" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0157
-is_a: MOD:00688
-is_a: MOD:02045
-is_a: MOD:02047
-is_a: MOD:00954
+is_a: MOD:00688 ! isopeptide crosslinked residues
+is_a: MOD:02045 ! crosslinked L-glutamic acid residue
+is_a: MOD:02047 ! crosslinked glycine residue
+is_a: MOD:00954 ! crosslinked residues with loss of water
 
 [Term]
 id: MOD:00366
@@ -9021,9 +9020,9 @@ property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:40
 xref: uniprot.ptm:PTM-0284
-is_a: MOD:00695
-is_a: MOD:00771
-is_a: MOD:00916
+is_a: MOD:00695 ! sulfated residue
+is_a: MOD:00771 ! residues isobaric at 166.98-167.00 Da
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:00367
@@ -9049,9 +9048,9 @@ property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:40
 xref: uniprot.ptm:PTM-0285
-is_a: MOD:00695
-is_a: MOD:00773
-is_a: MOD:00917
+is_a: MOD:00695 ! sulfated residue
+is_a: MOD:00773 ! residues isobaric at 181.00-181.02 Da
+is_a: MOD:00917 ! modified L-threonine residue
 
 [Term]
 id: MOD:00368
@@ -9075,8 +9074,8 @@ property_value: Origin "M" xsd:string
 property_value: Source "hypothetical" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:299
-is_a: MOD:00913
-is_a: MOD:01152
+is_a: MOD:00913 ! modified L-methionine residue
+is_a: MOD:01152 ! carboxylated residue
 
 [Term]
 id: MOD:00369
@@ -9103,9 +9102,9 @@ property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:1
 xref: uniprot.ptm:PTM-0232
-is_a: MOD:00644
-is_a: MOD:00647
-is_a: MOD:02003
+is_a: MOD:00644 ! mono O-acetylated residue
+is_a: MOD:00647 ! monoacetylated L-serine
+is_a: MOD:02003 ! O3-acylated L-serine
 
 [Term]
 id: MOD:00370
@@ -9133,7 +9132,7 @@ property_value: MassMono "161.047678" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0001
-is_a: MOD:00706
+is_a: MOD:00706 ! dehydrogenated tyrosine
 
 [Term]
 id: MOD:00371
@@ -9152,11 +9151,11 @@ property_value: MassAvg "1072.44" xsd:float
 property_value: MassMono "1071.888057" xsd:float
 property_value: Origin "D, D, E, E, E, H" xsd:string
 property_value: Source "hypothetical" xsd:string
-is_a: MOD:00740
-is_a: MOD:02066
-is_a: MOD:02068
-is_a: MOD:02070
-is_a: MOD:01482
+is_a: MOD:00740 ! manganese containing modified residue
+is_a: MOD:02066 ! metal or metal cluster coordinated L-aspartic acid residue
+is_a: MOD:02068 ! metal or metal cluster coordinated L-glutamic acid residue
+is_a: MOD:02070 ! metal or metal cluster coordinated L-histidine residue
+is_a: MOD:01482 ! calcium containing modified residue
 
 [Term]
 id: MOD:00372
@@ -9178,8 +9177,8 @@ property_value: MassAvg "324.34" xsd:float
 property_value: MassMono "324.111007" xsd:float
 property_value: Origin "Y, Y" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00692
-is_a: MOD:02058
+is_a: MOD:00692 ! uncategorized crosslinked residues
+is_a: MOD:02058 ! crosslinked L-tyrosine residue
 
 [Term]
 id: MOD:00373
@@ -9202,8 +9201,8 @@ property_value: MassMono "324.111007" xsd:float
 property_value: Origin "Y, Y" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0155
-is_a: MOD:00692
-is_a: MOD:02058
+is_a: MOD:00692 ! uncategorized crosslinked residues
+is_a: MOD:02058 ! crosslinked L-tyrosine residue
 
 [Term]
 id: MOD:00374
@@ -9228,8 +9227,8 @@ property_value: Origin "R" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:425
 xref: uniprot.ptm:PTM-0022
-is_a: MOD:00428
-is_a: MOD:00682
+is_a: MOD:00428 ! dihydroxylated residue
+is_a: MOD:00682 ! hydroxylated arginine
 
 [Term]
 id: MOD:00375
@@ -9254,8 +9253,8 @@ property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:425
 xref: uniprot.ptm:PTM-0036
-is_a: MOD:00428
-is_a: MOD:00681
+is_a: MOD:00428 ! dihydroxylated residue
+is_a: MOD:00681 ! hydroxylated lysine
 
 [Term]
 id: MOD:00376
@@ -9281,8 +9280,8 @@ property_value: MassMono "466.111432" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:405
-is_a: MOD:00909
-is_a: MOD:01165
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:01165 ! adenylated residue
 
 [Term]
 id: MOD:00377
@@ -9310,8 +9309,8 @@ property_value: Origin "H" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:417
 xref: uniprot.ptm:PTM-0500
-is_a: MOD:00909
-is_a: MOD:01166
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:01166 ! uridylated residue
 
 [Term]
 id: MOD:00378
@@ -9340,8 +9339,8 @@ property_value: Origin "D" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:447
 xref: uniprot.ptm:PTM-0064
-is_a: MOD:00904
-is_a: MOD:01161
+is_a: MOD:00904 ! modified L-aspartic acid residue
+is_a: MOD:01161 ! deoxygenated residue
 
 [Term]
 id: MOD:00379
@@ -9364,7 +9363,7 @@ property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: Unimod:448
 xref: uniprot.ptm:PTM-0276
-is_a: MOD:00916
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:00380
@@ -9386,8 +9385,8 @@ property_value: MassMono "1688.012718" xsd:float
 property_value: Origin "D" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:424
-is_a: MOD:02066
-is_a: MOD:01167
+is_a: MOD:02066 ! metal or metal cluster coordinated L-aspartic acid residue
+is_a: MOD:01167 ! molybdopterin guanine dinucleotide
 
 [Term]
 id: MOD:00381
@@ -9401,9 +9400,9 @@ property_value: MassAvg "1842.02" xsd:float
 property_value: MassMono "1841.957004" xsd:float
 property_value: Origin "U" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00746
-is_a: MOD:00748
-is_a: MOD:02073
+is_a: MOD:00746 ! tungsten containing modified residue
+is_a: MOD:00748 ! pterin modified residue
+is_a: MOD:02073 ! metal or metal cluster coordinated L-selenocysteine residue
 
 [Term]
 id: MOD:00382
@@ -9424,8 +9423,8 @@ property_value: MassMono "275.085424" xsd:float
 property_value: Origin "M, Y" xsd:string
 property_value: Source "hypothetical" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:02052
-is_a: MOD:02058
+is_a: MOD:02052 ! crosslinked L-methionine residue
+is_a: MOD:02058 ! crosslinked L-tyrosine residue
 
 [Term]
 id: MOD:00383
@@ -9449,9 +9448,9 @@ property_value: MassMono "166.037842" xsd:float
 property_value: Origin "E, G" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: uniprot.ptm:PTM-0014
-is_a: MOD:02045
-is_a: MOD:02047
-is_a: MOD:01882
+is_a: MOD:02045 ! crosslinked L-glutamic acid residue
+is_a: MOD:02047 ! crosslinked glycine residue
+is_a: MOD:01882 ! 5-imidazolinone ring crosslinked residues (Gly)
 
 [Term]
 id: MOD:00384
@@ -9477,9 +9476,9 @@ property_value: MassMono "168.035734" xsd:float
 property_value: Origin "G, M" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0015
-is_a: MOD:02047
-is_a: MOD:02052
-is_a: MOD:01882
+is_a: MOD:02047 ! crosslinked glycine residue
+is_a: MOD:02052 ! crosslinked L-methionine residue
+is_a: MOD:01882 ! 5-imidazolinone ring crosslinked residues (Gly)
 
 [Term]
 id: MOD:00385
@@ -9503,10 +9502,10 @@ property_value: MassMono "153.053826" xsd:float
 property_value: Origin "G, N" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: uniprot.ptm:PTM-0046
-is_a: MOD:02042
-is_a: MOD:02047
-is_a: MOD:01882
-is_a: MOD:00954
+is_a: MOD:02042 ! crosslinked L-asparagine residue
+is_a: MOD:02047 ! crosslinked glycine residue
+is_a: MOD:01882 ! 5-imidazolinone ring crosslinked residues (Gly)
+is_a: MOD:00954 ! crosslinked residues with loss of water
 
 [Term]
 id: MOD:00386
@@ -9530,10 +9529,10 @@ property_value: MassMono "167.105862" xsd:float
 property_value: Origin "G, K" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: uniprot.ptm:PTM-0048
-is_a: MOD:02047
-is_a: MOD:02051
-is_a: MOD:01882
-is_a: MOD:00954
+is_a: MOD:02047 ! crosslinked glycine residue
+is_a: MOD:02051 ! crosslinked L-lysine residue
+is_a: MOD:01882 ! 5-imidazolinone ring crosslinked residues (Gly)
+is_a: MOD:00954 ! crosslinked residues with loss of water
 
 [Term]
 id: MOD:00387
@@ -9558,9 +9557,9 @@ property_value: Origin "G, K" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0018
-is_a: MOD:02047
-is_a: MOD:02051
-is_a: MOD:01882
+is_a: MOD:02047 ! crosslinked glycine residue
+is_a: MOD:02051 ! crosslinked L-lysine residue
+is_a: MOD:01882 ! 5-imidazolinone ring crosslinked residues (Gly)
 
 [Term]
 id: MOD:00388
@@ -9573,8 +9572,8 @@ property_value: Origin "A" xsd:string
 property_value: Source "hypothetical" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0245
-is_a: MOD:00901
-is_a: MOD:01159
+is_a: MOD:00901 ! modified L-alanine residue
+is_a: MOD:01159 ! peptidoglycanated residue
 
 [Term]
 id: MOD:00389
@@ -9597,9 +9596,9 @@ property_value: Origin "P" xsd:string
 property_value: Source "hypothetical" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:122
-is_a: MOD:00409
-is_a: MOD:00915
-is_a: MOD:01696
+is_a: MOD:00409 ! N-formylated residue
+is_a: MOD:00915 ! modified L-proline residue
+is_a: MOD:01696 ! alpha-amino acylated residue
 
 [Term]
 id: MOD:00390
@@ -9624,8 +9623,8 @@ property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:449
 xref: uniprot.ptm:PTM-0234
-is_a: MOD:00668
-is_a: MOD:02003
+is_a: MOD:00668 ! O-decanoylated residue
+is_a: MOD:02003 ! O3-acylated L-serine
 
 [Term]
 id: MOD:00391
@@ -9651,8 +9650,8 @@ property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:426
 xref: uniprot.ptm:PTM-0240
-is_a: MOD:00669
-is_a: MOD:02004
+is_a: MOD:00669 ! O-octanoylated residue
+is_a: MOD:02004 ! O3-acylated L-threonine
 
 [Term]
 id: MOD:00392
@@ -9677,8 +9676,8 @@ property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:449
 xref: uniprot.ptm:PTM-0235
-is_a: MOD:00668
-is_a: MOD:02004
+is_a: MOD:00668 ! O-decanoylated residue
+is_a: MOD:02004 ! O3-acylated L-threonine
 
 [Term]
 id: MOD:00393
@@ -9686,7 +9685,7 @@ name: O-methylated residue
 def: "A protein modification that effectively replaces a hydroxyl group hydrogen with a methyl group to produce either an ether from an alcohol or an ester from an acid." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "OMeRes" EXACT PSI-MOD-label []
-is_a: MOD:00427
+is_a: MOD:00427 ! methylated residue
 
 [Term]
 id: MOD:00394
@@ -9704,15 +9703,15 @@ property_value: DiffMono "42.010565" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:1
-is_a: MOD:02078
+is_a: MOD:02078 ! acetylated residue
 
 [Term]
 id: MOD:00395
 name: thioester crosslinked residues
 def: "A protein modification that crosslinks two residues by formation of a thioester bond between a cysteine thiol and either an alpha-carbonyl, as in S-(L-methionyl-L-cysteine), or a sidechain carbonyl, as in S-(L-isoglutamyl)-L-cysteine." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00033
-is_a: MOD:02044
+is_a: MOD:00033 ! crosslinked residues
+is_a: MOD:02044 ! crosslinked L-cysteine residue
 
 [Term]
 id: MOD:00396
@@ -9720,7 +9719,7 @@ name: O-glycosylated residue
 def: "A protein modification that effectively replaces a residue hydrogen atom on an oxygen with a carbohydrate-like group through a glycosidic bond." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "OGlycoRes" EXACT PSI-MOD-label []
-is_a: MOD:00693
+is_a: MOD:00693 ! glycosylated residue
 
 [Term]
 id: MOD:00397
@@ -9735,7 +9734,7 @@ property_value: DiffMono "57.021464" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:4
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00398
@@ -9751,7 +9750,7 @@ property_value: DiffFormula "C 1 H 1 N 1 O 1" xsd:string
 property_value: DiffMono "43.005814" xsd:float
 property_value: Origin "X" xsd:string
 xref: Unimod:5
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:00399
@@ -9768,7 +9767,7 @@ property_value: DiffMono "58.005479" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:6
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00400
@@ -9786,7 +9785,7 @@ property_value: DiffFormula "H -1 N -1 O 1" xsd:string
 property_value: DiffMono "0.984016" xsd:float
 property_value: Origin "X" xsd:string
 xref: Unimod:7
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:00401
@@ -9803,8 +9802,8 @@ property_value: MassMono "589.260391" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:8
-is_a: MOD:01426
-is_a: MOD:01820
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
+is_a: MOD:01820 ! isotope tagged sufhydryl reagent modified cysteine
 
 [Term]
 id: MOD:00402
@@ -9821,8 +9820,8 @@ property_value: MassMono "597.310605" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:9
-is_a: MOD:01431
-is_a: MOD:01820
+is_a: MOD:01431 ! (2)H deuterium tagged reagent
+is_a: MOD:01820 ! isotope tagged sufhydryl reagent modified cysteine
 
 [Term]
 id: MOD:00403
@@ -9844,7 +9843,7 @@ property_value: Origin "M" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: Unimod:10
-is_a: MOD:00913
+is_a: MOD:00913 ! modified L-methionine residue
 
 [Term]
 id: MOD:00404
@@ -9865,8 +9864,8 @@ property_value: Origin "M" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: Unimod:11
-is_a: MOD:00601
-is_a: MOD:00913
+is_a: MOD:00601 ! cyclized residue
+is_a: MOD:00913 ! modified L-methionine residue
 
 [Term]
 id: MOD:00405
@@ -9884,8 +9883,8 @@ property_value: MassMono "553.284390" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:12
-is_a: MOD:01431
-is_a: MOD:01820
+is_a: MOD:01431 ! (2)H deuterium tagged reagent
+is_a: MOD:01820 ! isotope tagged sufhydryl reagent modified cysteine
 
 [Term]
 id: MOD:00406
@@ -9903,8 +9902,8 @@ property_value: MassMono "545.234176" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:13
-is_a: MOD:01426
-is_a: MOD:01820
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
+is_a: MOD:01820 ! isotope tagged sufhydryl reagent modified cysteine
 
 [Term]
 id: MOD:00407
@@ -9930,8 +9929,8 @@ property_value: DiffAvg "42.04" xsd:float
 property_value: DiffFormula "C 2 H 2 O 1" xsd:string
 property_value: DiffMono "42.010565" xsd:float
 property_value: Origin "X" xsd:string
-is_a: MOD:00394
-is_a: MOD:00670
+is_a: MOD:00394 ! monoacetylated residue
+is_a: MOD:00670 ! N-acylated residue
 
 [Term]
 id: MOD:00409
@@ -9946,8 +9945,8 @@ property_value: DiffAvg "28.01" xsd:float
 property_value: DiffFormula "C 1 O 1" xsd:string
 property_value: DiffMono "27.994915" xsd:float
 property_value: Origin "X" xsd:string
-is_a: MOD:00493
-is_a: MOD:00670
+is_a: MOD:00493 ! formylated residue
+is_a: MOD:00670 ! N-acylated residue
 
 [Term]
 id: MOD:00410
@@ -9965,8 +9964,8 @@ property_value: MassMono "202.077599" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:17
-is_a: MOD:00848
-is_a: MOD:00905
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00411
@@ -10007,8 +10006,8 @@ property_value: MassMono "517.202876" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:20
-is_a: MOD:00848
-is_a: MOD:00905
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00414
@@ -10028,8 +10027,8 @@ property_value: MassAvg "170.22" xsd:float
 property_value: MassMono "170.116761" xsd:float
 property_value: Origin "R" xsd:string
 xref: Unimod:34
-is_a: MOD:00599
-is_a: MOD:00658
+is_a: MOD:00599 ! monomethylated residue
+is_a: MOD:00658 ! methylated arginine
 
 [Term]
 id: MOD:00415
@@ -10057,8 +10056,8 @@ property_value: DiffMono "-18.010565" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:23
-is_a: MOD:00432
-is_a: MOD:00704
+is_a: MOD:00432 ! modified residue with neutral loss of phosphate
+is_a: MOD:00704 ! dehydrated residue
 
 [Term]
 id: MOD:00417
@@ -10082,7 +10081,7 @@ property_value: MassMono "174.046299" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:24
-is_a: MOD:00905
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00418
@@ -10097,8 +10096,8 @@ property_value: DiffMono "119.037114" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:25
-is_a: MOD:00649
-is_a: MOD:00848
+is_a: MOD:00649 ! acylated residue
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00419
@@ -10121,8 +10120,8 @@ property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:26
-is_a: MOD:00601
-is_a: MOD:00905
+is_a: MOD:00601 ! cyclized residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00420
@@ -10154,8 +10153,8 @@ property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:27
 xref: uniprot.ptm:PTM-0262
-is_a: MOD:00906
-is_a: MOD:01048
+is_a: MOD:00906 ! modified L-glutamic acid residue
+is_a: MOD:01048 ! 2-pyrrolidone-5-carboxylic acid
 
 [Term]
 id: MOD:00421
@@ -10163,7 +10162,7 @@ name: C-glycosylated residue
 def: "A protein modification that effectively replaces a residue hydrogen atom on a carbon with a carbohydrate-like group through a glycosidic bond." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "CGlycoRes" EXACT PSI-MOD-label []
-is_a: MOD:00693
+is_a: MOD:00693 ! glycosylated residue
 
 [Term]
 id: MOD:00422
@@ -10180,8 +10179,8 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:29
-is_a: MOD:01696
-is_a: MOD:01813
+is_a: MOD:01696 ! alpha-amino acylated residue
+is_a: MOD:01813 ! morpholine-2-acetylated residue
 
 [Term]
 id: MOD:00423
@@ -10197,7 +10196,7 @@ property_value: DiffFormula "H -1 Na 1" xsd:string
 property_value: DiffMono "21.981944" xsd:float
 property_value: Origin "X" xsd:string
 xref: Unimod:30
-is_a: MOD:00747
+is_a: MOD:00747 ! sodium containing modified residue
 
 [Term]
 id: MOD:00424
@@ -10220,8 +10219,8 @@ property_value: MassMono "208.067034" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:31
-is_a: MOD:00848
-is_a: MOD:00905
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00425
@@ -10236,14 +10235,14 @@ property_value: DiffFormula "O 1" xsd:string
 property_value: DiffMono "15.994915" xsd:float
 property_value: Origin "X" xsd:string
 xref: Unimod:35
-is_a: MOD:00677
+is_a: MOD:00677 ! hydroxylated residue
 
 [Term]
 id: MOD:00426
 name: S-glycosylated residue
 def: "A protein modification that effectively replaces a residue hydrogen atom on a sulfur with a carbohydrate-like group through a glycosidic bond." [PubMed:18688235]
 synonym: "SGlycoRes" EXACT PSI-MOD-label []
-is_a: MOD:00693
+is_a: MOD:00693 ! glycosylated residue
 
 [Term]
 id: MOD:00427
@@ -10253,7 +10252,7 @@ comment: From DeltaMass: Average Mass: 14 Average Mass Change:14 References:Meth
 subset: PSI-MOD-slim
 synonym: "MeRes" EXACT PSI-MOD-label []
 synonym: "Methylation (N terminus, N epsilon of Lysine, O of Serine, Threonine or C terminus, N of Asparagine)" EXACT DeltaMass-label []
-is_a: MOD:00001
+is_a: MOD:00001 ! alkylated residue
 
 [Term]
 id: MOD:00428
@@ -10268,7 +10267,7 @@ property_value: DiffFormula "C 0 H 0 N 0 O 2" xsd:string
 property_value: DiffMono "31.989829" xsd:float
 property_value: Origin "X" xsd:string
 xref: Unimod:425
-is_a: MOD:00677
+is_a: MOD:00677 ! hydroxylated residue
 
 [Term]
 id: MOD:00429
@@ -10285,7 +10284,7 @@ property_value: DiffFormula "C 2 H 4" xsd:string
 property_value: DiffMono "28.031300" xsd:float
 property_value: Origin "X" xsd:string
 xref: Unimod:36
-is_a: MOD:00427
+is_a: MOD:00427 ! methylated residue
 
 [Term]
 id: MOD:00430
@@ -10301,7 +10300,7 @@ property_value: DiffFormula "C 3 H 6" xsd:string
 property_value: DiffMono "42.046950" xsd:float
 property_value: Origin "X" xsd:string
 xref: Unimod:37
-is_a: MOD:00427
+is_a: MOD:00427 ! methylated residue
 
 [Term]
 id: MOD:00431
@@ -10309,7 +10308,7 @@ name: modified residue with a secondary neutral loss
 def: "Covalent modification of, or a change resulting in an alteration of the measured molecular mass of, a peptide or protein amino acid residue with a secondary loss of a neutral molecular fragment." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "NLModRes" EXACT PSI-MOD-label []
-is_a: MOD:01157
+is_a: MOD:01157 ! protein modification categorized by amino acid modified
 
 [Term]
 id: MOD:00432
@@ -10317,7 +10316,7 @@ name: modified residue with neutral loss of phosphate
 def: "Covalent modification of, or a change resulting in an alteration of the measured molecular mass of, a peptide or protein amino acid residue with a secondary loss of a neutral trihydrogen phosphate molecular fragment." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "dPhosModRes" EXACT PSI-MOD-label []
-is_a: MOD:00431
+is_a: MOD:00431 ! modified residue with a secondary neutral loss
 
 [Term]
 id: MOD:00433
@@ -10329,8 +10328,8 @@ property_value: DiffAvg "162.14" xsd:float
 property_value: DiffFormula "C 6 H 10 N 0 O 5" xsd:string
 property_value: DiffMono "162.052823" xsd:float
 property_value: Origin "X" xsd:string
-is_a: MOD:00761
-is_a: MOD:00726
+is_a: MOD:00761 ! monohexosylated residue
+is_a: MOD:00726 ! glucosylated residue
 
 [Term]
 id: MOD:00434
@@ -10346,7 +10345,7 @@ synonym: "O-Glycosyl-" EXACT DeltaMass-label []
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:41
-is_a: MOD:00693
+is_a: MOD:00693 ! glycosylated residue
 
 [Term]
 id: MOD:00435
@@ -10362,8 +10361,8 @@ property_value: MassAvg "69.06" xsd:float
 property_value: MassMono "69.021464" xsd:float
 property_value: Origin "MOD:00046" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01151
-relationship: derives_from MOD:00046
+is_a: MOD:01151 ! phosphorylated residue with neutral loss of phosphate
+relationship: derives_from MOD:00046 ! O-phospho-L-serine
 
 [Term]
 id: MOD:00436
@@ -10378,7 +10377,7 @@ property_value: DiffFormula "C 8 H 13 N 1 O 5" xsd:string
 property_value: DiffMono "203.079373" xsd:float
 property_value: Origin "X" xsd:string
 xref: GNO:G29068FM
-is_a: MOD:00693
+is_a: MOD:00693 ! glycosylated residue
 
 [Term]
 id: MOD:00437
@@ -10396,7 +10395,7 @@ property_value: DiffMono "204.187801" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:44
-is_a: MOD:00703
+is_a: MOD:00703 ! isoprenylated residue
 
 [Term]
 id: MOD:00438
@@ -10415,8 +10414,8 @@ property_value: DiffMono "210.198365" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:45
-is_a: MOD:00649
-is_a: MOD:01155
+is_a: MOD:00649 ! acylated residue
+is_a: MOD:01155 ! lipoconjugated residue
 
 [Term]
 id: MOD:00439
@@ -10432,9 +10431,9 @@ property_value: MassAvg "83.09" xsd:float
 property_value: MassMono "83.037114" xsd:float
 property_value: Origin "MOD:00047" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00917
-is_a: MOD:01151
-relationship: derives_from MOD:00047
+is_a: MOD:00917 ! modified L-threonine residue
+is_a: MOD:01151 ! phosphorylated residue with neutral loss of phosphate
+relationship: derives_from MOD:00047 ! O-phospho-L-threonine
 
 [Term]
 id: MOD:00440
@@ -10452,8 +10451,8 @@ property_value: DiffFormula "C 16 H 30 O 1" xsd:string
 property_value: DiffMono "238.229666" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00649
-is_a: MOD:01155
+is_a: MOD:00649 ! acylated residue
+is_a: MOD:01155 ! lipoconjugated residue
 
 [Term]
 id: MOD:00441
@@ -10471,7 +10470,7 @@ property_value: DiffMono "272.250401" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:48
-is_a: MOD:00703
+is_a: MOD:00703 ! isoprenylated residue
 
 [Term]
 id: MOD:00442
@@ -10486,8 +10485,8 @@ property_value: MassAvg "142.20" xsd:float
 property_value: MassMono "142.110613" xsd:float
 property_value: Origin "R" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00431
-is_a: MOD:00902
+is_a: MOD:00431 ! modified residue with a secondary neutral loss
+is_a: MOD:00902 ! modified L-arginine residue
 
 [Term]
 id: MOD:00443
@@ -10502,8 +10501,8 @@ property_value: MassAvg "140.17" xsd:float
 property_value: MassMono "140.082387" xsd:float
 property_value: Origin "R" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00431
-is_a: MOD:00902
+is_a: MOD:00431 ! modified residue with a secondary neutral loss
+is_a: MOD:00902 ! modified L-arginine residue
 
 [Term]
 id: MOD:00444
@@ -10522,8 +10521,8 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:51
-is_a: MOD:00899
-relationship: has_functional_parent MOD:01144
+is_a: MOD:00899 ! N-palmitoyl-S-diacylglycerol-L-cysteine
+relationship: has_functional_parent MOD:01144 ! S-(sn-1-2,3-dipalmitoylglycerol)-L-cysteine
 
 [Term]
 id: MOD:00445
@@ -10542,8 +10541,8 @@ property_value: MassMono "170.116761" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:52
-is_a: MOD:00848
-is_a: MOD:00912
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:00446
@@ -10558,7 +10557,7 @@ property_value: DiffMono "156.115030" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:53
-is_a: MOD:01155
+is_a: MOD:01155 ! lipoconjugated residue
 
 [Term]
 id: MOD:00447
@@ -10573,7 +10572,7 @@ property_value: DiffFormula "C 6 H 8 O 6" xsd:string
 property_value: DiffMono "176.032088" xsd:float
 property_value: Origin "X" xsd:string
 xref: Unimod:54
-is_a: MOD:00764
+is_a: MOD:00764 ! glycoconjugated residue
 
 [Term]
 id: MOD:00448
@@ -10586,8 +10585,8 @@ property_value: DiffAvg "203.19" xsd:float
 property_value: DiffFormula "C 8 H 13 N 1 O 5" xsd:string
 property_value: DiffMono "203.079373" xsd:float
 property_value: Origin "X" xsd:string
-is_a: MOD:00733
-is_a: MOD:01673
+is_a: MOD:00733 ! N-acetylaminoglucosylated
+is_a: MOD:01673 ! N-acetylaminohexosylated residue
 
 [Term]
 id: MOD:00449
@@ -10602,7 +10601,7 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:56
-is_a: MOD:01431
+is_a: MOD:01431 ! (2)H deuterium tagged reagent
 
 [Term]
 id: MOD:00450
@@ -10628,7 +10627,7 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:58
-is_a: MOD:01894
+is_a: MOD:01894 ! propanoylated residue
 
 [Term]
 id: MOD:00452
@@ -10646,9 +10645,9 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:59
-relationship: derives_from MOD:00451
-is_a: MOD:01428
-is_a: MOD:01426
+relationship: derives_from MOD:00451 ! alpha-amino propanoylated residue
+is_a: MOD:01428 ! (13)C isotope tagged reagent
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
 
 [Term]
 id: MOD:00453
@@ -10662,7 +10661,7 @@ property_value: DiffMono "127.099714" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:60
-is_a: MOD:01426
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
 
 [Term]
 id: MOD:00454
@@ -10679,7 +10678,7 @@ property_value: MassMono "258.213507" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:61
-is_a: MOD:01426
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
 
 [Term]
 id: MOD:00455
@@ -10693,7 +10692,7 @@ property_value: DiffMono "133.137375" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:62
-is_a: MOD:01426
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
 
 [Term]
 id: MOD:00456
@@ -10710,7 +10709,7 @@ property_value: MassMono "264.251168" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:63
-is_a: MOD:01426
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
 
 [Term]
 id: MOD:00457
@@ -10725,9 +10724,9 @@ property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:64
-relationship: derives_from MOD:01029
-is_a: MOD:01696
-is_a: MOD:01426
+relationship: derives_from MOD:01029 ! succinylated residue
+is_a: MOD:01696 ! alpha-amino acylated residue
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
 
 [Term]
 id: MOD:00458
@@ -10742,9 +10741,9 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:65
-relationship: derives_from MOD:01029
-is_a: MOD:01696
-is_a: MOD:01426
+relationship: derives_from MOD:01029 ! succinylated residue
+is_a: MOD:01696 ! alpha-amino acylated residue
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
 
 [Term]
 id: MOD:00459
@@ -10757,10 +10756,10 @@ property_value: DiffFormula "(13)C 4 H 4 O 3" xsd:string
 property_value: DiffMono "104.029463" xsd:float
 property_value: Origin "X" xsd:string
 xref: Unimod:66
-relationship: derives_from MOD:01029
-is_a: MOD:01696
-is_a: MOD:01428
-is_a: MOD:01426
+relationship: derives_from MOD:01029 ! succinylated residue
+is_a: MOD:01696 ! alpha-amino acylated residue
+is_a: MOD:01428 ! (13)C isotope tagged reagent
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
 
 [Term]
 id: MOD:00460
@@ -10792,7 +10791,7 @@ property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:345
 xref: uniprot.ptm:PTM-0634
-is_a: MOD:00708
+is_a: MOD:00708 ! sulfur oxygenated L-cysteine
 
 [Term]
 id: MOD:00461
@@ -10808,7 +10807,7 @@ property_value: DiffFormula "H -1 N 1 O 2" xsd:string
 property_value: DiffMono "44.985078" xsd:float
 property_value: Origin "X" xsd:string
 xref: Unimod:354
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00462
@@ -10828,7 +10827,7 @@ property_value: MassMono "190.074228" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:351
-is_a: MOD:00918
+is_a: MOD:00918 ! modified L-tryptophan residue
 
 [Term]
 id: MOD:00463
@@ -10847,8 +10846,8 @@ property_value: MassMono "206.069142" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:350
-is_a: MOD:00679
-is_a: MOD:00918
+is_a: MOD:00679 ! carbon oxygenated residue
+is_a: MOD:00918 ! modified L-tryptophan residue
 
 [Term]
 id: MOD:00464
@@ -10870,8 +10869,8 @@ property_value: MassMono "218.069142" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:425
-is_a: MOD:00679
-is_a: MOD:00918
+is_a: MOD:00679 ! carbon oxygenated residue
+is_a: MOD:00918 ! modified L-tryptophan residue
 
 [Term]
 id: MOD:00465
@@ -10891,16 +10890,16 @@ property_value: MassMono "179.058243" xsd:float
 property_value: Origin "F" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:425
-is_a: MOD:00428
-is_a: MOD:00914
+is_a: MOD:00428 ! dihydroxylated residue
+is_a: MOD:00914 ! modified L-phenylalanine residue
 
 [Term]
 id: MOD:00466
 name: glycosylsphingolipidinositolated residue
 def: "A protein modification that effectively converts a residue to a glycosylsphingolipidinositolethanolamidated." [PubMed:12626404, PubMed:18688235, PubMed:8404891]
 synonym: "GSIRes" EXACT PSI-MOD-label []
-is_a: MOD:00764
-is_a: MOD:01155
+is_a: MOD:00764 ! glycoconjugated residue
+is_a: MOD:01155 ! lipoconjugated residue
 
 [Term]
 id: MOD:00467
@@ -10914,7 +10913,7 @@ property_value: DiffMono "225.093583" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:89
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00468
@@ -10928,7 +10927,7 @@ property_value: DiffMono "338.177647" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:90
-is_a: MOD:01426
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
 
 [Term]
 id: MOD:00469
@@ -10942,7 +10941,7 @@ property_value: DiffMono "348.240415" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:91
-is_a: MOD:01431
+is_a: MOD:01431 ! (2)H deuterium tagged reagent
 
 [Term]
 id: MOD:00470
@@ -10956,7 +10955,7 @@ property_value: DiffMono "339.161663" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:92
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00471
@@ -10970,7 +10969,7 @@ property_value: DiffMono "601.206247" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:93
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00472
@@ -10987,7 +10986,7 @@ property_value: MassMono "196.132411" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:94
-is_a: MOD:01426
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
 
 [Term]
 id: MOD:00473
@@ -11004,7 +11003,7 @@ property_value: MassMono "200.157518" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:95
-is_a: MOD:01426
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
 
 [Term]
 id: MOD:00474
@@ -11024,8 +11023,8 @@ property_value: MassMono "177.065129" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:97
-relationship: derives_from MOD:00417
-is_a: MOD:01426
+relationship: derives_from MOD:00417 ! S-carboxamidoethyl-L-cysteine
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
 
 [Term]
 id: MOD:00475
@@ -11042,8 +11041,8 @@ property_value: MassMono "178.074228" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:342
-is_a: MOD:00919
-is_a: MOD:02039
+is_a: MOD:00919 ! modified L-tyrosine residue
+is_a: MOD:02039 ! aminated residue
 
 [Term]
 id: MOD:00476
@@ -11056,8 +11055,8 @@ property_value: DiffFormula "C 6 H 10 O 5" xsd:string
 property_value: DiffMono "162.052823" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00761
-is_a: MOD:00728
+is_a: MOD:00761 ! monohexosylated residue
+is_a: MOD:00728 ! galactosylated residue
 
 [Term]
 id: MOD:00477
@@ -11075,8 +11074,8 @@ property_value: MassMono "84.044939" xsd:float
 property_value: Origin "P" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:360
-is_a: MOD:00683
-is_a: MOD:00915
+is_a: MOD:00683 ! dehydrogenated residue
+is_a: MOD:00915 ! modified L-proline residue
 
 [Term]
 id: MOD:00478
@@ -11097,9 +11096,9 @@ property_value: MassMono "113.047678" xsd:float
 property_value: Origin "P" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:35
-is_a: MOD:00679
-is_a: MOD:00915
-is_a: MOD:01440
+is_a: MOD:00679 ! carbon oxygenated residue
+is_a: MOD:00915 ! modified L-proline residue
+is_a: MOD:01440 ! glutamyl semialdehyde
 
 [Term]
 id: MOD:00479
@@ -11118,8 +11117,8 @@ property_value: MassMono "113.047678" xsd:float
 property_value: Origin "R" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:344
-is_a: MOD:00902
-is_a: MOD:01440
+is_a: MOD:00902 ! modified L-arginine residue
+is_a: MOD:01440 ! glutamyl semialdehyde
 
 [Term]
 id: MOD:00480
@@ -11138,7 +11137,7 @@ property_value: MassMono "330.136176" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:105
-is_a: MOD:01426
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
 
 [Term]
 id: MOD:00481
@@ -11157,7 +11156,7 @@ property_value: MassMono "339.166370" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:106
-is_a: MOD:01428
+is_a: MOD:01428 ! (13)C isotope tagged reagent
 
 [Term]
 id: MOD:00482
@@ -11183,7 +11182,7 @@ property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:122
 xref: uniprot.ptm:PTM-0212
-is_a: MOD:00913
+is_a: MOD:00913 ! modified L-methionine residue
 
 [Term]
 id: MOD:00483
@@ -11201,8 +11200,8 @@ property_value: MassMono "228.056863" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:108
-is_a: MOD:00848
-is_a: MOD:00905
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00484
@@ -11219,8 +11218,8 @@ property_value: MassMono "482.267525" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:112
-is_a: MOD:00848
-is_a: MOD:00912
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:00485
@@ -11237,8 +11236,8 @@ property_value: MassMono "480.251875" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:113
-is_a: MOD:00848
-is_a: MOD:00912
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:00486
@@ -11255,8 +11254,8 @@ property_value: MassMono "468.251875" xsd:float
 property_value: Origin "P" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:114
-is_a: MOD:00848
-is_a: MOD:00915
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00915 ! modified L-proline residue
 
 [Term]
 id: MOD:00487
@@ -11273,8 +11272,8 @@ property_value: MassMono "466.236225" xsd:float
 property_value: Origin "P" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:115
-is_a: MOD:00848
-is_a: MOD:00915
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00915 ! modified L-proline residue
 
 [Term]
 id: MOD:00488
@@ -11290,8 +11289,8 @@ property_value: MassAvg "466.60" xsd:float
 property_value: MassMono "466.236225" xsd:float
 property_value: Origin "R" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
-is_a: MOD:00902
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00902 ! modified L-arginine residue
 
 [Term]
 id: MOD:00489
@@ -11308,8 +11307,8 @@ property_value: MassMono "468.251875" xsd:float
 property_value: Origin "R" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:117
-is_a: MOD:00848
-is_a: MOD:00902
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00902 ! modified L-arginine residue
 
 [Term]
 id: MOD:00490
@@ -11322,7 +11321,7 @@ property_value: DiffFormula "C 20 H 34 N 4 O 4 S 3" xsd:string
 property_value: DiffMono "490.174219" xsd:float
 property_value: Origin "X" xsd:string
 xref: Unimod:118
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00491
@@ -11339,9 +11338,9 @@ property_value: MassMono "419.147272" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:119
-is_a: MOD:00848
-is_a: MOD:00861
-is_a: MOD:00905
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00861 ! phosphorus containing modified residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00492
@@ -11361,10 +11360,10 @@ property_value: MassMono "242.137890" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:121
-is_a: MOD:02047
-is_a: MOD:02051
-is_a: MOD:01875
-relationship: derives_from MOD:01148
+is_a: MOD:02047 ! crosslinked glycine residue
+is_a: MOD:02051 ! crosslinked L-lysine residue
+is_a: MOD:01875 ! N6-acylated L-lysine
+relationship: derives_from MOD:01148 ! ubiquitinylated lysine
 
 [Term]
 id: MOD:00493
@@ -11381,7 +11380,7 @@ property_value: DiffFormula "C 1 O 1" xsd:string
 property_value: DiffMono "27.994915" xsd:float
 property_value: Origin "X" xsd:string
 xref: Unimod:122
-is_a: MOD:00649
+is_a: MOD:00649 ! acylated residue
 
 [Term]
 id: MOD:00494
@@ -11398,8 +11397,8 @@ property_value: MassMono "448.107100" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:123
-is_a: MOD:00905
-is_a: MOD:01426
+is_a: MOD:00905 ! modified L-cysteine residue
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
 
 [Term]
 id: MOD:00495
@@ -11416,8 +11415,8 @@ property_value: MassMono "454.127229" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:124
-is_a: MOD:00905
-is_a: MOD:01426
+is_a: MOD:00905 ! modified L-cysteine residue
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
 
 [Term]
 id: MOD:00496
@@ -11449,8 +11448,8 @@ property_value: MassMono "216.093249" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:126
-is_a: MOD:00848
-is_a: MOD:00912
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:00498
@@ -11462,7 +11461,7 @@ synonym: "Fluorophenylalanyl" EXACT DeltaMass-label []
 synonym: "FRes" EXACT PSI-MOD-label []
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00694
+is_a: MOD:00694 ! halogen containing residue
 
 [Term]
 id: MOD:00499
@@ -11479,8 +11478,8 @@ property_value: MassMono "491.091297" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:128
-is_a: MOD:00848
-is_a: MOD:00905
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00500
@@ -11497,7 +11496,7 @@ property_value: DiffFormula "H -1 I 1" xsd:string
 property_value: DiffMono "125.896648" xsd:float
 property_value: Origin "X" xsd:string
 xref: Unimod:129
-is_a: MOD:00755
+is_a: MOD:00755 ! iodinated residue
 
 [Term]
 id: MOD:00501
@@ -11513,7 +11512,7 @@ property_value: DiffFormula "H -2 I 2" xsd:string
 property_value: DiffMono "251.793295" xsd:float
 property_value: Origin "X" xsd:string
 xref: Unimod:130
-is_a: MOD:00755
+is_a: MOD:00755 ! iodinated residue
 
 [Term]
 id: MOD:00502
@@ -11531,7 +11530,7 @@ property_value: DiffMono "377.689943" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:131
-is_a: MOD:00755
+is_a: MOD:00755 ! iodinated residue
 
 [Term]
 id: MOD:00503
@@ -11552,8 +11551,8 @@ property_value: Origin "G" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:134
-is_a: MOD:00908
-is_a: MOD:01696
+is_a: MOD:00908 ! modified glycine residue
+is_a: MOD:01696 ! alpha-amino acylated residue
 
 [Term]
 id: MOD:00504
@@ -11574,8 +11573,8 @@ property_value: Origin "G" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:135
-is_a: MOD:00908
-is_a: MOD:01696
+is_a: MOD:00908 ! modified glycine residue
+is_a: MOD:01696 ! alpha-amino acylated residue
 
 [Term]
 id: MOD:00505
@@ -11591,7 +11590,7 @@ property_value: DiffMono "104.026215" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:136
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00506
@@ -11609,8 +11608,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:137
 xref: GNO:G02815KT
-is_a: MOD:00725
-is_a: MOD:00160
+is_a: MOD:00725 ! complex glycosylation
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:00507
@@ -11654,7 +11653,7 @@ property_value: DiffMono "41.026549" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:141
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00510
@@ -11673,8 +11672,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:142
 xref: GNO:G00194GV
-is_a: MOD:00725
-is_a: MOD:00160
+is_a: MOD:00725 ! complex glycosylation
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:00511
@@ -11692,8 +11691,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:143
 xref: GNO:G27391WQ
-is_a: MOD:00725
-is_a: MOD:00160
+is_a: MOD:00725 ! complex glycosylation
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:00512
@@ -11711,8 +11710,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:144
 xref: GNO:G39365VM
-is_a: MOD:00725
-is_a: MOD:00160
+is_a: MOD:00725 ! complex glycosylation
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:00513
@@ -11730,8 +11729,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:145
 xref: GNO:G74392IM
-is_a: MOD:00725
-is_a: MOD:00160
+is_a: MOD:00725 ! complex glycosylation
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:00514
@@ -11749,8 +11748,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:146
 xref: GNO:G54129SE
-is_a: MOD:00725
-is_a: MOD:00160
+is_a: MOD:00725 ! complex glycosylation
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:00515
@@ -11768,8 +11767,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:147
 xref: GNO:G06042JP
-is_a: MOD:00725
-is_a: MOD:00160
+is_a: MOD:00725 ! complex glycosylation
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:00516
@@ -11787,8 +11786,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:148
 xref: GNO:G58001LT
-is_a: MOD:00725
-is_a: MOD:00160
+is_a: MOD:00725 ! complex glycosylation
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:00517
@@ -11804,7 +11803,7 @@ property_value: DiffMono "657.235437" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 xref: GNO:G17015OC
-is_a: MOD:00725
+is_a: MOD:00725 ! complex glycosylation
 
 [Term]
 id: MOD:00518
@@ -11822,8 +11821,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:150
 xref: GNO:G90423UY
-is_a: MOD:00725
-is_a: MOD:00160
+is_a: MOD:00725 ! complex glycosylation
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:00519
@@ -11841,8 +11840,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:151
 xref: GNO:G54968WM
-is_a: MOD:00725
-is_a: MOD:00160
+is_a: MOD:00725 ! complex glycosylation
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:00520
@@ -11860,8 +11859,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:152
 xref: GNO:G94583DZ
-is_a: MOD:00725
-is_a: MOD:00160
+is_a: MOD:00725 ! complex glycosylation
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:00521
@@ -11879,8 +11878,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:153
 xref: GNO:G53434XO
-is_a: MOD:00725
-is_a: MOD:00160
+is_a: MOD:00725 ! complex glycosylation
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:00522
@@ -11898,8 +11897,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:154
 xref: GNO:G64686LL
-is_a: MOD:00725
-is_a: MOD:00160
+is_a: MOD:00725 ! complex glycosylation
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:00523
@@ -11917,8 +11916,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:155
 xref: GNO:G84825UQ
-is_a: MOD:00725
-is_a: MOD:00160
+is_a: MOD:00725 ! complex glycosylation
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:00524
@@ -11936,8 +11935,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:156
 xref: GNO:G05460KC
-is_a: MOD:00725
-is_a: MOD:00160
+is_a: MOD:00725 ! complex glycosylation
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:00525
@@ -11955,8 +11954,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:157
 xref: GNO:G18999EB
-is_a: MOD:00725
-is_a: MOD:00160
+is_a: MOD:00725 ! complex glycosylation
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:00526
@@ -11974,8 +11973,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:158
 xref: GNO:G93579XB
-is_a: MOD:00725
-is_a: MOD:00160
+is_a: MOD:00725 ! complex glycosylation
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:00527
@@ -11995,8 +11994,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:159
 xref: GNO:G28681TP
-is_a: MOD:00725
-is_a: MOD:00160
+is_a: MOD:00725 ! complex glycosylation
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:00528
@@ -12011,7 +12010,7 @@ property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:160
 xref: GNO:G23729WG
-is_a: MOD:00725
+is_a: MOD:00725 ! complex glycosylation
 
 [Term]
 id: MOD:00529
@@ -12029,8 +12028,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:161
 xref: GNO:G88520YF
-is_a: MOD:00725
-is_a: MOD:00160
+is_a: MOD:00725 ! complex glycosylation
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:00530
@@ -12049,8 +12048,8 @@ property_value: MassMono "178.984935" xsd:float
 property_value: Origin "M" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:162
-is_a: MOD:00007
-is_a: MOD:00913
+is_a: MOD:00007 ! selenium substitution for sulfur
+is_a: MOD:00913 ! modified L-methionine residue
 
 [Term]
 id: MOD:00531
@@ -12068,7 +12067,7 @@ property_value: MassMono "117.031189" xsd:float
 property_value: Origin "N" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:170
-is_a: MOD:01293
+is_a: MOD:01293 ! 1x(18)O labeled deamidated L-asparagine
 
 [Term]
 id: MOD:00532
@@ -12085,7 +12084,7 @@ property_value: MassMono "345.087891" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:171
-is_a: MOD:01426
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
 
 [Term]
 id: MOD:00533
@@ -12102,7 +12101,7 @@ property_value: MassMono "339.067762" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:172
-is_a: MOD:01426
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
 
 [Term]
 id: MOD:00534
@@ -12117,7 +12116,7 @@ property_value: DiffMono "218.167065" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:176
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00535
@@ -12132,7 +12131,7 @@ property_value: DiffMono "87.050656" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:178
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00536
@@ -12163,14 +12162,14 @@ property_value: MassAvg "71.08" xsd:float
 property_value: MassMono "71.037114" xsd:float
 property_value: Origin "T" xsd:string
 xref: Unimod:659
-is_a: MOD:00917
+is_a: MOD:00917 ! modified L-threonine residue
 
 [Term]
 id: MOD:00538
 name: protein modification categorized by isobaric sets
 def: "Modified amino acid residues groups into isobaric sets at particular mass resolution cut-offs." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00000
+is_a: MOD:00000 ! protein modification
 
 [Term]
 id: MOD:00539
@@ -12196,7 +12195,7 @@ property_value: DiffMono "9.030194" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:184
-is_a: MOD:00842
+is_a: MOD:00842 ! (13)C labeled residue
 
 [Term]
 id: MOD:00541
@@ -12213,10 +12212,10 @@ property_value: MassMono "252.059853" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:185
-is_a: MOD:00919
-is_a: MOD:00842
-relationship: derives_from MOD:00540
-relationship: derives_from MOD:00048
+is_a: MOD:00919 ! modified L-tyrosine residue
+is_a: MOD:00842 ! (13)C labeled residue
+relationship: derives_from MOD:00540 ! 9x(13)C labeled residue
+relationship: derives_from MOD:00048 ! O4'-phospho-L-tyrosine
 
 [Term]
 id: MOD:00542
@@ -12233,8 +12232,8 @@ property_value: MassMono "288.122240" xsd:float
 property_value: Origin "R" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:186
-is_a: MOD:00902
-is_a: MOD:00848
+is_a: MOD:00902 ! modified L-arginine residue
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00543
@@ -12252,8 +12251,8 @@ property_value: MassMono "438.153934" xsd:float
 property_value: Origin "R" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:187
-is_a: MOD:00902
-is_a: MOD:00848
+is_a: MOD:00902 ! modified L-arginine residue
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00544
@@ -12268,7 +12267,7 @@ property_value: DiffMono "6.020129" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:188
-is_a: MOD:00842
+is_a: MOD:00842 ! (13)C labeled residue
 
 [Term]
 id: MOD:00545
@@ -12295,7 +12294,7 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: Unimod:193
-is_a: MOD:00847
+is_a: MOD:00847 ! (18)O disubstituted residue
 
 [Term]
 id: MOD:00547
@@ -12309,7 +12308,7 @@ property_value: DiffMono "170.048013" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:194
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00548
@@ -12327,7 +12326,7 @@ property_value: MassMono "274.158923" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:195
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00549
@@ -12346,7 +12345,7 @@ property_value: MassMono "277.177753" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:196
-is_a: MOD:01431
+is_a: MOD:01431 ! (2)H deuterium tagged reagent
 
 [Term]
 id: MOD:00550
@@ -12363,7 +12362,7 @@ property_value: MassMono "287.166748" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:197
-is_a: MOD:01426
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
 
 [Term]
 id: MOD:00551
@@ -12380,7 +12379,7 @@ property_value: MassMono "292.198132" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:198
-is_a: MOD:01431
+is_a: MOD:01431 ! (2)H deuterium tagged reagent
 
 [Term]
 id: MOD:00552
@@ -12396,7 +12395,7 @@ property_value: DiffMono "32.056407" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:199
-is_a: MOD:00839
+is_a: MOD:00839 ! (2)H deuterium labeled residue
 
 [Term]
 id: MOD:00553
@@ -12412,7 +12411,7 @@ property_value: DiffMono "75.980528" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:200
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00554
@@ -12534,7 +12533,7 @@ property_value: DiffMono "85.052764" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:211
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00562
@@ -12548,7 +12547,7 @@ property_value: DiffMono "90.084148" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:212
-is_a: MOD:01431
+is_a: MOD:01431 ! (2)H deuterium tagged reagent
 
 [Term]
 id: MOD:00563
@@ -12561,8 +12560,8 @@ property_value: DiffAvg "203.19" xsd:float
 property_value: DiffFormula "C 8 H 13 N 1 O 5" xsd:string
 property_value: DiffMono "203.079373" xsd:float
 property_value: Origin "X" xsd:string
-is_a: MOD:00734
-is_a: MOD:01673
+is_a: MOD:00734 ! N-acetylaminogalactosylated
+is_a: MOD:01673 ! N-acetylaminohexosylated residue
 
 [Term]
 id: MOD:00564
@@ -12592,7 +12591,7 @@ property_value: MassMono "115.026943" xsd:float
 property_value: Origin "N" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:7
-is_a: MOD:00903
+is_a: MOD:00903 ! modified L-asparagine residue
 
 [Term]
 id: MOD:00566
@@ -12610,8 +12609,8 @@ property_value: MassMono "399.025225" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:243
-is_a: MOD:00905
-is_a: MOD:00848
+is_a: MOD:00905 ! modified L-cysteine residue
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00567
@@ -12643,14 +12642,14 @@ id: MOD:00569
 name: residues isobaric at a resolution below 0.000001 Da
 def: "Natural or modified residues that are isobaric at a resolution below 0.000001 Da." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00770
+is_a: MOD:00770 ! residues isobaric at a resolution below 0.01 Da
 
 [Term]
 id: MOD:00570
 name: residues isobaric at 71.037114 Da
 def: "Natural or modified residues with a mass of 71.037114 Da." [PubMed:18688235]
-is_a: MOD:00569
-is_a: MOD:00769
+is_a: MOD:00569 ! residues isobaric at a resolution below 0.000001 Da
+is_a: MOD:00769 ! residues isobaric at 71.0-71.1 Da
 
 [Term]
 id: MOD:00571
@@ -12670,9 +12669,9 @@ property_value: MassMono "112.039853" xsd:float
 property_value: Origin "P" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:359
-is_a: MOD:00679
-is_a: MOD:00915
-is_a: MOD:01048
+is_a: MOD:00679 ! carbon oxygenated residue
+is_a: MOD:00915 ! modified L-proline residue
+is_a: MOD:01048 ! 2-pyrrolidone-5-carboxylic acid
 
 [Term]
 id: MOD:00572
@@ -12689,8 +12688,8 @@ property_value: MassMono "355.167811" xsd:float
 property_value: Origin "R" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:343
-is_a: MOD:00848
-is_a: MOD:00902
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00902 ! modified L-arginine residue
 
 [Term]
 id: MOD:00573
@@ -12708,8 +12707,8 @@ property_value: MassMono "369.183461" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:353
-is_a: MOD:00848
-is_a: MOD:00912
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:00574
@@ -12727,8 +12726,8 @@ property_value: MassMono "355.167811" xsd:float
 property_value: Origin "P" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:357
-is_a: MOD:00848
-is_a: MOD:00915
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00915 ! modified L-proline residue
 
 [Term]
 id: MOD:00575
@@ -12746,8 +12745,8 @@ property_value: MassMono "341.152161" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:361
-is_a: MOD:00848
-is_a: MOD:00917
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00917 ! modified L-threonine residue
 
 [Term]
 id: MOD:00576
@@ -12761,7 +12760,7 @@ property_value: DiffMono "70.041865" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:253
-is_a: MOD:00649
+is_a: MOD:00649 ! acylated residue
 
 [Term]
 id: MOD:00577
@@ -12778,8 +12777,8 @@ property_value: MassMono "666.490465" xsd:float
 property_value: Origin "K, K, K, K, K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:254
-is_a: MOD:02051
-is_a: MOD:00692
+is_a: MOD:02051 ! crosslinked L-lysine residue
+is_a: MOD:00692 ! uncategorized crosslinked residues
 
 [Term]
 id: MOD:00578
@@ -12838,7 +12837,7 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: Unimod:258
-is_a: MOD:00845
+is_a: MOD:00845 ! (18)O substituted residue
 
 [Term]
 id: MOD:00582
@@ -12856,9 +12855,9 @@ property_value: MassMono "136.109162" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:259
-is_a: MOD:00842
-is_a: MOD:00843
-is_a: MOD:00912
+is_a: MOD:00842 ! (13)C labeled residue
+is_a: MOD:00843 ! (15)N labeled residue
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:00583
@@ -12872,8 +12871,8 @@ property_value: DiffMono "95.943487" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:260
-is_a: MOD:00860
-is_a: MOD:00861
+is_a: MOD:00860 ! sulfur containing modified residue
+is_a: MOD:00861 ! phosphorus containing modified residue
 
 [Term]
 id: MOD:00584
@@ -12888,7 +12887,7 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:261
-is_a: MOD:00841
+is_a: MOD:00841 ! isothiocyanate reagent derivatized residue
 
 [Term]
 id: MOD:00585
@@ -12903,7 +12902,7 @@ property_value: DiffMono "3.018830" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:262
-is_a: MOD:00786
+is_a: MOD:00786 ! deuterium substituted residue
 
 [Term]
 id: MOD:00586
@@ -12917,7 +12916,7 @@ property_value: DiffMono "121.035006" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:264
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00587
@@ -12936,9 +12935,9 @@ property_value: MassMono "166.109380" xsd:float
 property_value: Origin "R" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:267
-is_a: MOD:00842
-is_a: MOD:00843
-is_a: MOD:00902
+is_a: MOD:00842 ! (13)C labeled residue
+is_a: MOD:00843 ! (15)N labeled residue
+is_a: MOD:00902 ! modified L-arginine residue
 
 [Term]
 id: MOD:00588
@@ -12955,8 +12954,8 @@ property_value: MassMono "105.082223" xsd:float
 property_value: Origin "V" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:268
-is_a: MOD:00920
-is_a: MOD:01809
+is_a: MOD:00920 ! modified L-valine residue
+is_a: MOD:01809 ! 5x(13)C,1x(15)N labeled residue
 
 [Term]
 id: MOD:00589
@@ -12973,9 +12972,9 @@ property_value: MassMono "157.095642" xsd:float
 property_value: Origin "F" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:269
-is_a: MOD:00842
-is_a: MOD:00843
-is_a: MOD:00914
+is_a: MOD:00842 ! (13)C labeled residue
+is_a: MOD:00843 ! (15)N labeled residue
+is_a: MOD:00914 ! modified L-phenylalanine residue
 
 [Term]
 id: MOD:00590
@@ -13018,7 +13017,7 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:272
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00593
@@ -13043,8 +13042,8 @@ id: MOD:00594
 name: residues isobaric at 113.047678 Da
 def: "Natural or modified resiues with a mass of 113.047678 Da." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00569
-is_a: MOD:00624
+is_a: MOD:00569 ! residues isobaric at a resolution below 0.000001 Da
+is_a: MOD:00624 ! residues isobaric at 113.0-113.1 Da
 
 [Term]
 id: MOD:00595
@@ -13057,8 +13056,8 @@ property_value: DiffFormula "C 6 H 10 O 5" xsd:string
 property_value: DiffMono "162.052823" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00727
-is_a: MOD:00761
+is_a: MOD:00727 ! mannosylated residue
+is_a: MOD:00761 ! monohexosylated residue
 
 [Term]
 id: MOD:00596
@@ -13074,7 +13073,7 @@ property_value: DiffMono "183.035400" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:276
-is_a: MOD:01652
+is_a: MOD:01652 ! sulfonyl halide reagent derivatized residue
 
 [Term]
 id: MOD:00597
@@ -13106,7 +13105,7 @@ property_value: MassMono "147.035400" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:278
-is_a: MOD:00905
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00599
@@ -13121,7 +13120,7 @@ property_value: DiffFormula "C 1 H 2" xsd:string
 property_value: DiffMono "14.015650" xsd:float
 property_value: Origin "X" xsd:string
 xref: Unimod:34
-is_a: MOD:00427
+is_a: MOD:00427 ! methylated residue
 
 [Term]
 id: MOD:00600
@@ -13140,8 +13139,8 @@ property_value: MassMono "157.073893" xsd:float
 property_value: Origin "E" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:280
-is_a: MOD:00906
-is_a: MOD:01339
+is_a: MOD:00906 ! modified L-glutamic acid residue
+is_a: MOD:01339 ! ethylated residue
 
 [Term]
 id: MOD:00601
@@ -13149,7 +13148,7 @@ name: cyclized residue
 def: "A protein modification that effectively produces an heterocyclic amino acid with a covalent bond between the side chain and either its alpha amino or 1-carboxyl group, possibly breaking the peptide chain." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "CycRes" EXACT PSI-MOD-label []
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:00602
@@ -13157,7 +13156,7 @@ name: N-methylated residue
 def: "A protein modification that effectively replaces a hydrogen atom of a residue amino or imino group with an methyl group." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "NMeRes" EXACT PSI-MOD-label []
-is_a: MOD:00427
+is_a: MOD:00427 ! methylated residue
 
 [Term]
 id: MOD:00603
@@ -13188,9 +13187,9 @@ property_value: MassMono "144.123167" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:284
-is_a: MOD:00839
-is_a: MOD:00912
-relationship: derives_from MOD:00085
+is_a: MOD:00839 ! (2)H deuterium labeled residue
+is_a: MOD:00912 ! modified L-lysine residue
+relationship: derives_from MOD:00085 ! N6-methyl-L-lysine
 
 [Term]
 id: MOD:00605
@@ -13205,7 +13204,7 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: Unimod:285
-is_a: MOD:01426
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
 
 [Term]
 id: MOD:00606
@@ -13220,7 +13219,7 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: Unimod:286
-is_a: MOD:01428
+is_a: MOD:01428 ! (13)C isotope tagged reagent
 
 [Term]
 id: MOD:00607
@@ -13239,7 +13238,7 @@ property_value: Origin "W" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: Unimod:288
-is_a: MOD:00918
+is_a: MOD:00918 ! modified L-tryptophan residue
 
 [Term]
 id: MOD:00608
@@ -13250,7 +13249,7 @@ synonym: "Biotin-PEO-Amine" RELATED Unimod-interim []
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:289
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00609
@@ -13267,8 +13266,8 @@ property_value: MassMono "531.200768" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:290
-is_a: MOD:00905
-is_a: MOD:00848
+is_a: MOD:00905 ! modified L-cysteine residue
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00610
@@ -13285,9 +13284,9 @@ property_value: MassMono "304.979828" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:291
-is_a: MOD:00848
-is_a: MOD:02067
-is_a: MOD:01075
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
+is_a: MOD:01075 ! mercury containing modified residue
 
 [Term]
 id: MOD:00611
@@ -13301,7 +13300,7 @@ property_value: DiffMono "322.020217" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:292
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00612
@@ -13315,8 +13314,8 @@ property_value: DiffMono "145.019749" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:293
-is_a: MOD:00649
-is_a: MOD:00848
+is_a: MOD:00649 ! acylated residue
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00613
@@ -13333,8 +13332,8 @@ property_value: MassMono "429.150446" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:294
-is_a: MOD:00848
-is_a: MOD:00905
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00614
@@ -13351,7 +13350,7 @@ property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:295
 xref: GNO:G49112ZN
-is_a: MOD:00736
+is_a: MOD:00736 ! deoxyhexosylated residue
 
 [Term]
 id: MOD:00615
@@ -13372,7 +13371,7 @@ id: MOD:00616
 name: residues isobaric at a resolution below 0.1 Da
 def: "Natural or modified residues that are isobaric at a resolution below 0.1 Da." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00538
+is_a: MOD:00538 ! protein modification categorized by isobaric sets
 
 [Term]
 id: MOD:00617
@@ -13388,7 +13387,7 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: Unimod:298
-is_a: MOD:00839
+is_a: MOD:00839 ! (2)H deuterium labeled residue
 
 [Term]
 id: MOD:00618
@@ -13406,8 +13405,8 @@ property_value: MassMono "230.069142" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:299
-is_a: MOD:00918
-is_a: MOD:01152
+is_a: MOD:00918 ! modified L-tryptophan residue
+is_a: MOD:01152 ! carboxylated residue
 
 [Term]
 id: MOD:00619
@@ -13438,8 +13437,8 @@ property_value: MassMono "293.083412" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:301
-is_a: MOD:00848
-is_a: MOD:00905
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00621
@@ -13453,7 +13452,7 @@ property_value: DiffMono "170.036779" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:302
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00622
@@ -13472,8 +13471,8 @@ property_value: MassMono "179.007471" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:303
-is_a: MOD:00848
-is_a: MOD:00905
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00623
@@ -13491,15 +13490,15 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:305
 xref: GNO:G25987BV
-is_a: MOD:00725
-is_a: MOD:00160
+is_a: MOD:00725 ! complex glycosylation
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:00624
 name: residues isobaric at 113.0-113.1 Da
 def: "Natural or modified residues with a mass of 113.0-113.1 Da." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00616
+is_a: MOD:00616 ! residues isobaric at a resolution below 0.1 Da
 
 [Term]
 id: MOD:00625
@@ -13513,7 +13512,7 @@ property_value: DiffMono "111.032028" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:314
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00626
@@ -13527,7 +13526,7 @@ property_value: DiffMono "421.073242" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:478
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00627
@@ -13547,8 +13546,8 @@ property_value: MassMono "206.141913" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:316
-is_a: MOD:00848
-is_a: MOD:00912
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:00628
@@ -13560,7 +13559,7 @@ property_value: DiffMono "324.105647" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 xref: GNO:G90627TW
-is_a: MOD:00725
+is_a: MOD:00725 ! complex glycosylation
 
 [Term]
 id: MOD:00629
@@ -13578,8 +13577,8 @@ property_value: MassMono "190.110613" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:318
-is_a: MOD:00848
-is_a: MOD:00912
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:00630
@@ -13594,7 +13593,7 @@ property_value: DiffMono "54.010565" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:319
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00631
@@ -13609,7 +13608,7 @@ property_value: DiffMono "143.058243" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:320
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00632
@@ -13640,8 +13639,8 @@ property_value: MassMono "816.102263" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:323
-is_a: MOD:00848
-is_a: MOD:00905
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00634
@@ -13656,7 +13655,7 @@ property_value: DiffMono "122.990948" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:324
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00635
@@ -13673,9 +13672,9 @@ property_value: MassMono "659.348157" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:325
-is_a: MOD:00848
-is_a: MOD:00861
-is_a: MOD:00916
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00861 ! phosphorus containing modified residue
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:00636
@@ -13693,7 +13692,7 @@ property_value: MassMono "131.040485" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:327
-is_a: MOD:00916
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:00637
@@ -13710,10 +13709,10 @@ property_value: MassMono "174.138946" xsd:float
 property_value: Origin "R" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:329
-is_a: MOD:00839
-is_a: MOD:00842
-is_a: MOD:00902
-relationship: derives_from MOD:00414
+is_a: MOD:00839 ! (2)H deuterium labeled residue
+is_a: MOD:00842 ! (13)C labeled residue
+is_a: MOD:00902 ! modified L-arginine residue
+relationship: derives_from MOD:00414 ! monomethylated L-arginine
 
 [Term]
 id: MOD:00638
@@ -13730,10 +13729,10 @@ property_value: MassMono "192.176781" xsd:float
 property_value: Origin "R" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:330
-is_a: MOD:00839
-is_a: MOD:00842
-is_a: MOD:00902
-relationship: derives_from MOD:00783
+is_a: MOD:00839 ! (2)H deuterium labeled residue
+is_a: MOD:00842 ! (13)C labeled residue
+is_a: MOD:00902 ! modified L-arginine residue
+relationship: derives_from MOD:00783 ! dimethylated L-arginine
 
 [Term]
 id: MOD:00639
@@ -13747,8 +13746,8 @@ property_value: DiffMono "525.142895" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:332
-is_a: MOD:00848
-is_a: MOD:00861
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00861 ! phosphorus containing modified residue
 
 [Term]
 id: MOD:00640
@@ -13765,9 +13764,9 @@ property_value: MassMono "554.233935" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:333
-is_a: MOD:00848
-is_a: MOD:00861
-is_a: MOD:00916
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00861 ! phosphorus containing modified residue
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:00641
@@ -13795,9 +13794,9 @@ property_value: DiffMono "158.130680" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:335
-is_a: MOD:00848
-is_a: MOD:01155
-relationship: derives_from MOD:00446
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:01155 ! lipoconjugated residue
+relationship: derives_from MOD:00446 ! 4-hydroxynonenal adduct
 
 [Term]
 id: MOD:00643
@@ -13811,7 +13810,7 @@ property_value: DiffMono "13.031634" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:337
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00644
@@ -13824,8 +13823,8 @@ property_value: DiffFormula "C 2 H 2 O 1" xsd:string
 property_value: DiffMono "42.010565" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00394
-is_a: MOD:00671
+is_a: MOD:00394 ! monoacetylated residue
+is_a: MOD:00671 ! O-acylated residue
 
 [Term]
 id: MOD:00645
@@ -13838,8 +13837,8 @@ property_value: DiffFormula "C 2 H 2 O 1 S 0" xsd:string
 property_value: DiffMono "42.010565" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00394
-is_a: MOD:00672
+is_a: MOD:00394 ! monoacetylated residue
+is_a: MOD:00672 ! S-acylated residue
 
 [Term]
 id: MOD:00646
@@ -13855,8 +13854,8 @@ property_value: MassAvg "145.18" xsd:float
 property_value: MassMono "145.019749" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00394
-is_a: MOD:00905
+is_a: MOD:00394 ! monoacetylated residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00647
@@ -13869,8 +13868,8 @@ property_value: DiffFormula "C 2 H 2 N 0 O 1" xsd:string
 property_value: DiffMono "42.010565" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00394
-is_a: MOD:00916
+is_a: MOD:00394 ! monoacetylated residue
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:00648
@@ -13890,9 +13889,9 @@ property_value: MassMono "172.060983" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:02080
-relationship: has_functional_parent MOD:00060
-relationship: has_functional_parent MOD:00369
+is_a: MOD:02080 ! diacetylated L-serine
+relationship: has_functional_parent MOD:00060 ! N-acetyl-L-serine
+relationship: has_functional_parent MOD:00369 ! O-acetyl-L-serine
 
 [Term]
 id: MOD:00649
@@ -13900,7 +13899,7 @@ name: acylated residue
 def: "A protein modification that effectively replaces a hydrogen atom with an acyl group." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "AcylRes" EXACT PSI-MOD-label []
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:00650
@@ -13913,8 +13912,8 @@ property_value: DiffFormula "C 14 H 26 O 1" xsd:string
 property_value: DiffMono "210.198365" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00438
-is_a: MOD:00670
+is_a: MOD:00438 ! myristoylated residue
+is_a: MOD:00670 ! N-acylated residue
 
 [Term]
 id: MOD:00651
@@ -13928,8 +13927,8 @@ property_value: DiffFormula "C 16 H 30 O 1" xsd:string
 property_value: DiffMono "238.229666" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00440
-is_a: MOD:00670
+is_a: MOD:00440 ! palmitoylated residue
+is_a: MOD:00670 ! N-acylated residue
 
 [Term]
 id: MOD:00652
@@ -13943,8 +13942,8 @@ property_value: DiffFormula "C 16 H 30 O 1" xsd:string
 property_value: DiffMono "238.229666" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00440
-is_a: MOD:00671
+is_a: MOD:00440 ! palmitoylated residue
+is_a: MOD:00671 ! O-acylated residue
 
 [Term]
 id: MOD:00653
@@ -13958,8 +13957,8 @@ property_value: DiffFormula "C 16 H 30 O 1 S 0" xsd:string
 property_value: DiffMono "238.229666" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00440
-is_a: MOD:00672
+is_a: MOD:00440 ! palmitoylated residue
+is_a: MOD:00672 ! S-acylated residue
 
 [Term]
 id: MOD:00654
@@ -13967,7 +13966,7 @@ name: S-methylated residue
 def: "a protein modification that effectively replaces a sulfanyl group with a methylsulfanyl group" [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "SMeRes" EXACT PSI-MOD-label []
-is_a: MOD:00427
+is_a: MOD:00427 ! methylated residue
 
 [Term]
 id: MOD:00655
@@ -13979,15 +13978,15 @@ property_value: DiffFormula "C 14 H 26 O 1 S 0" xsd:string
 property_value: DiffMono "210.198365" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00438
-is_a: MOD:00672
+is_a: MOD:00438 ! myristoylated residue
+is_a: MOD:00672 ! S-acylated residue
 
 [Term]
 id: MOD:00656
 name: C-methylated residue
 def: "A protein modification that effectively replaces a residue hydrocarbyl hydrogen with an methyl group." [PubMed:18688235]
 synonym: "CMeRes" EXACT PSI-MOD-label []
-is_a: MOD:00427
+is_a: MOD:00427 ! methylated residue
 
 [Term]
 id: MOD:00657
@@ -14018,9 +14017,9 @@ property_value: Origin "Q" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:528
 xref: uniprot.ptm:PTM-0127
-is_a: MOD:01369
-is_a: MOD:01453
-relationship: has_functional_parent MOD:00659
+is_a: MOD:01369 ! deamidated and methyl esterified residue
+is_a: MOD:01453 ! L-glutamic acid 5-methyl ester
+relationship: has_functional_parent MOD:00659 ! methylated glutamine
 
 [Term]
 id: MOD:00658
@@ -14030,8 +14029,8 @@ subset: PSI-MOD-slim
 synonym: "MeArg" EXACT PSI-MOD-label []
 property_value: Origin "R" xsd:string
 xref: uniprot.ptm:PTM-0238
-is_a: MOD:00427
-is_a: MOD:00902
+is_a: MOD:00427 ! methylated residue
+is_a: MOD:00902 ! modified L-arginine residue
 
 [Term]
 id: MOD:00659
@@ -14041,8 +14040,8 @@ subset: PSI-MOD-slim
 synonym: "MeGln" EXACT PSI-MOD-label []
 property_value: Origin "Q" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00427
-is_a: MOD:00907
+is_a: MOD:00427 ! methylated residue
+is_a: MOD:00907 ! modified L-glutamine residue
 
 [Term]
 id: MOD:00660
@@ -14052,8 +14051,8 @@ subset: PSI-MOD-slim
 synonym: "MeCys" EXACT PSI-MOD-label []
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00427
-is_a: MOD:00905
+is_a: MOD:00427 ! methylated residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00661
@@ -14063,8 +14062,8 @@ subset: PSI-MOD-slim
 synonym: "MeHis" EXACT PSI-MOD-label []
 property_value: Origin "H" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00427
-is_a: MOD:00909
+is_a: MOD:00427 ! methylated residue
+is_a: MOD:00909 ! modified L-histidine residue
 
 [Term]
 id: MOD:00662
@@ -14074,8 +14073,8 @@ subset: PSI-MOD-slim
 synonym: "MeLeu" EXACT PSI-MOD-label []
 property_value: Origin "L" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00427
-is_a: MOD:00911
+is_a: MOD:00427 ! methylated residue
+is_a: MOD:00911 ! modified L-leucine residue
 
 [Term]
 id: MOD:00663
@@ -14086,15 +14085,15 @@ synonym: "MeLys" EXACT PSI-MOD-label []
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0193
-is_a: MOD:00427
-is_a: MOD:00912
+is_a: MOD:00427 ! methylated residue
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:00664
 name: stereoisomerized residue
 def: "A protein modification that effectively replaces a residue L-enantiomer (stereoisomer) with a D-enantiomer or with a different diastereomeric isomer." [PubMed:18688235]
 synonym: "D-Res" EXACT PSI-MOD-label []
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:00665
@@ -14104,8 +14103,8 @@ subset: PSI-MOD-slim
 synonym: "MeAla" EXACT PSI-MOD-label []
 property_value: Origin "A" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00427
-is_a: MOD:00901
+is_a: MOD:00427 ! methylated residue
+is_a: MOD:00901 ! modified L-alanine residue
 
 [Term]
 id: MOD:00666
@@ -14118,8 +14117,8 @@ property_value: DiffFormula "C 8 H 14 N 0 O 1" xsd:string
 property_value: DiffMono "126.104465" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00649
-is_a: MOD:01155
+is_a: MOD:00649 ! acylated residue
+is_a: MOD:01155 ! lipoconjugated residue
 
 [Term]
 id: MOD:00667
@@ -14131,8 +14130,8 @@ property_value: DiffFormula "C 10 H 18 N 0 O 1" xsd:string
 property_value: DiffMono "154.135765" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00649
-is_a: MOD:01155
+is_a: MOD:00649 ! acylated residue
+is_a: MOD:01155 ! lipoconjugated residue
 
 [Term]
 id: MOD:00668
@@ -14147,8 +14146,8 @@ property_value: DiffMono "154.135765" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:449
-is_a: MOD:00667
-is_a: MOD:00671
+is_a: MOD:00667 ! decanoylated residue
+is_a: MOD:00671 ! O-acylated residue
 
 [Term]
 id: MOD:00669
@@ -14164,8 +14163,8 @@ property_value: DiffMono "126.104465" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:426
-is_a: MOD:00666
-is_a: MOD:00671
+is_a: MOD:00666 ! octanoylated residue
+is_a: MOD:00671 ! O-acylated residue
 
 [Term]
 id: MOD:00670
@@ -14173,7 +14172,7 @@ name: N-acylated residue
 def: "A protein modification that effectively replaces a residue alpha-amino- or alpha-imino-hydrogen with an acyl group." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "NAcylRes" EXACT PSI-MOD-label []
-is_a: MOD:00649
+is_a: MOD:00649 ! acylated residue
 
 [Term]
 id: MOD:00671
@@ -14181,7 +14180,7 @@ name: O-acylated residue
 def: "A protein modification that effectively replaces a residue hydroxyl group with a acyloxy group." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "OAcylRes" EXACT PSI-MOD-label []
-is_a: MOD:00649
+is_a: MOD:00649 ! acylated residue
 
 [Term]
 id: MOD:00672
@@ -14189,7 +14188,7 @@ name: S-acylated residue
 def: "A protein modification that effectively replaces a residue sulfanyl group with an acylsulfanyl group." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "SAcylRes" EXACT PSI-MOD-label []
-is_a: MOD:00649
+is_a: MOD:00649 ! acylated residue
 
 [Term]
 id: MOD:00673
@@ -14199,8 +14198,8 @@ subset: PSI-MOD-slim
 synonym: "MeAsn" EXACT PSI-MOD-label []
 property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00427
-is_a: MOD:00903
+is_a: MOD:00427 ! methylated residue
+is_a: MOD:00903 ! modified L-asparagine residue
 
 [Term]
 id: MOD:00674
@@ -14211,7 +14210,7 @@ property_value: DiffAvg "-0.98" xsd:float
 property_value: DiffFormula "C 0 H 1 N 1 O -1" xsd:string
 property_value: DiffMono "-0.984016" xsd:float
 property_value: Origin "X" xsd:string
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:00675
@@ -14220,7 +14219,7 @@ def: "A protein modification that effectively either removes neutral hydrogen at
 subset: PSI-MOD-slim
 synonym: "OxRes" EXACT PSI-MOD-label []
 property_value: Origin "X" xsd:string
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:00676
@@ -14229,7 +14228,7 @@ def: "A protein modification that effectively adds oxygen atoms to a residue wit
 subset: PSI-MOD-slim
 synonym: "OxyRes" EXACT PSI-MOD-label []
 property_value: Origin "X" xsd:string
-is_a: MOD:00675
+is_a: MOD:00675 ! oxidized residue
 
 [Term]
 id: MOD:00677
@@ -14240,7 +14239,7 @@ subset: PSI-MOD-slim
 synonym: "Hydroxylation (of delta C of Lysine, beta C of Tryptophan, C3 or C4 of Proline, beta C of Aspartate)" EXACT DeltaMass-label []
 synonym: "HyRes" EXACT PSI-MOD-label []
 property_value: Origin "X" xsd:string
-is_a: MOD:00679
+is_a: MOD:00679 ! carbon oxygenated residue
 
 [Term]
 id: MOD:00678
@@ -14249,8 +14248,8 @@ def: "A protein modification that effectively converts an L-proline residue to a
 subset: PSI-MOD-slim
 synonym: "HyPro" EXACT PSI-MOD-label []
 property_value: Origin "P" xsd:string
-is_a: MOD:00677
-is_a: MOD:00915
+is_a: MOD:00677 ! hydroxylated residue
+is_a: MOD:00915 ! modified L-proline residue
 
 [Term]
 id: MOD:00679
@@ -14258,7 +14257,7 @@ name: carbon oxygenated residue
 def: "A protein modification that effectively adds oxygen atoms to a carbon atom of a residue and removes hydrogen atoms." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "COxyRes" EXACT PSI-MOD-label []
-is_a: MOD:00676
+is_a: MOD:00676 ! oxygenated residue
 
 [Term]
 id: MOD:00680
@@ -14266,7 +14265,7 @@ name: sulfur oxygenated residue
 def: "A protein modification that effectively adds oxygen atoms to a sulfur atom of a residue without removing hydrogen atoms." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "SOxyRes" EXACT PSI-MOD-label []
-is_a: MOD:00676
+is_a: MOD:00676 ! oxygenated residue
 
 [Term]
 id: MOD:00681
@@ -14275,8 +14274,8 @@ def: "A protein modification that effectively converts an L-lysine residue to a
 subset: PSI-MOD-slim
 synonym: "HyLys" EXACT PSI-MOD-label []
 property_value: Origin "K" xsd:string
-is_a: MOD:00677
-is_a: MOD:00912
+is_a: MOD:00677 ! hydroxylated residue
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:00682
@@ -14285,8 +14284,8 @@ def: "A protein modification that effectively converts an L-arginine residue to
 synonym: "HyArg" EXACT PSI-MOD-label []
 property_value: Origin "R" xsd:string
 xref: uniprot.ptm:PTM-0498
-is_a: MOD:00677
-is_a: MOD:00902
+is_a: MOD:00677 ! hydroxylated residue
+is_a: MOD:00902 ! modified L-arginine residue
 
 [Term]
 id: MOD:00683
@@ -14295,7 +14294,7 @@ def: "A protein modification that effectively removes neutral hydrogen atoms (pr
 subset: PSI-MOD-slim
 synonym: "dHRes" EXACT PSI-MOD-label []
 property_value: Origin "X" xsd:string
-is_a: MOD:00675
+is_a: MOD:00675 ! oxidized residue
 
 [Term]
 id: MOD:00684
@@ -14319,8 +14318,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:7
 xref: uniprot.ptm:PTM-0116
-is_a: MOD:00400
-is_a: MOD:00903
+is_a: MOD:00400 ! deamidated residue
+is_a: MOD:00903 ! modified L-asparagine residue
 
 [Term]
 id: MOD:00685
@@ -14346,8 +14345,8 @@ property_value: Origin "Q" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:7
 xref: uniprot.ptm:PTM-0117
-is_a: MOD:00400
-is_a: MOD:00907
+is_a: MOD:00400 ! deamidated residue
+is_a: MOD:00907 ! modified L-glutamine residue
 
 [Term]
 id: MOD:00686
@@ -14371,48 +14370,48 @@ property_value: MassMono "150.953635" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:162
-is_a: MOD:00007
-is_a: MOD:00905
+is_a: MOD:00007 ! selenium substitution for sulfur
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00687
 name: thioether crosslinked residues
 def: "A protein modification that crosslinks two residues by formation of a thioether bond between a cysteine thiol and either an alkyl C as in lanthionine, or an aryl C as 2'-(S-cysteinyl)-L-histidine." [PubMed:18688235]
-is_a: MOD:00033
-is_a: MOD:02044
+is_a: MOD:00033 ! crosslinked residues
+is_a: MOD:02044 ! crosslinked L-cysteine residue
 
 [Term]
 id: MOD:00688
 name: isopeptide crosslinked residues
 def: "A protein modification that crosslinks two residues with an amide bond where either the donor amino or carboxyl is not an alpha group." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00033
+is_a: MOD:00033 ! crosslinked residues
 
 [Term]
 id: MOD:00689
 name: disulfide crosslinked residues
 def: "A protein modification that crosslinks two cysteine residues by formation of a disulfide bond." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:01619
+is_a: MOD:01619 ! multisulfide crosslinked residues
 
 [Term]
 id: MOD:00690
 name: oxazole/thiazole ring crosslinked residues
 def: "A protein modification that crosslinks two residues by formation of an oxazole or thiazole ring." [PubMed:18688235]
-is_a: MOD:00033
+is_a: MOD:00033 ! crosslinked residues
 
 [Term]
 id: MOD:00691
 name: 5-imidazolinone ring crosslinked residues
 def: "A protein modification that crosslinks two residues by formation of an 5-imidazolinone ring." [PubMed:18688235]
-is_a: MOD:00033
+is_a: MOD:00033 ! crosslinked residues
 
 [Term]
 id: MOD:00692
 name: uncategorized crosslinked residues
 def: "A protein crosslink modification that is not chemically categorized." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00033
+is_a: MOD:00033 ! crosslinked residues
 
 [Term]
 id: MOD:00693
@@ -14421,7 +14420,7 @@ def: "A protein modification that effectively replaces a hydrogen atom with an c
 subset: PSI-MOD-slim
 synonym: "GlycoRes" EXACT PSI-MOD-label []
 property_value: Source "natural" xsd:string
-is_a: MOD:00764
+is_a: MOD:00764 ! glycoconjugated residue
 
 [Term]
 id: MOD:00694
@@ -14430,7 +14429,7 @@ def: "A protein modification that effectively substitutes a halogen atom for a h
 subset: PSI-MOD-slim
 synonym: "halogenated residue" EXACT PSI-MOD-alternate []
 synonym: "HalRes" EXACT PSI-MOD-label []
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:00695
@@ -14448,7 +14447,7 @@ property_value: DiffMono "79.956815" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:40
-is_a: MOD:00860
+is_a: MOD:00860 ! sulfur containing modified residue
 
 [Term]
 id: MOD:00696
@@ -14465,7 +14464,7 @@ property_value: DiffFormula "H 1 O 3 P 1" xsd:string
 property_value: DiffMono "79.966331" xsd:float
 property_value: Origin "X" xsd:string
 xref: Unimod:21
-is_a: MOD:00861
+is_a: MOD:00861 ! phosphorus containing modified residue
 
 [Term]
 id: MOD:00697
@@ -14477,7 +14476,7 @@ synonym: "Flavin adenine dinucleotide" RELATED Unimod-description []
 synonym: "FlavRes" EXACT PSI-MOD-label []
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:00698
@@ -14485,7 +14484,7 @@ name: metal or metal cluster containing modified residue
 def: "A protein modification that effectively substitutes a metal atom or a metal cluster for hydrogen atoms, or coordinates a metal ion." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "MetalRes" EXACT PSI-MOD-label []
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:00699
@@ -14493,14 +14492,14 @@ name: porphyrin modified residue
 def: "A protein modification that effectively results from forming an adduct with a compound containing a porphyrin group." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "PorphRes" EXACT PSI-MOD-label []
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:00700
 name: tetrapyrrole modified residue
 def: "A protein modification that effectively results from forming an adduct with a compound containing a tetrapyrrole group." [PubMed:18688235]
 synonym: "TetrapyrRes" EXACT PSI-MOD-label []
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:00701
@@ -14508,7 +14507,7 @@ name: nucleotide or nucleic acid modified residue
 def: "A protein modification that effectively results from forming an adduct with a compound containing a nucleotide or a polynucleotide through formation of either a phosphodiester bond, a phosphoramide ester bond, or a glycosidic bond." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "NucRes" EXACT PSI-MOD-label []
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:00702
@@ -14518,7 +14517,7 @@ comment: In SILAC (stable isotope labelling of amino acids in cell culture), the
 subset: PSI-MOD-slim
 synonym: "IsoTagRes" EXACT PSI-MOD-label []
 synonym: "SILAC" EXACT PSI-MOD-alternate []
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:00703
@@ -14526,8 +14525,8 @@ name: isoprenylated residue
 def: "A protein modification that effectively replaces a hydrogen atom with a group derived from an isoprene polymer, such as a geranyl (C10), farnesyl (C15) or geranylgeranyl (C20) group." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "IpRes" EXACT PSI-MOD-label []
-is_a: MOD:00001
-is_a: MOD:01155
+is_a: MOD:00001 ! alkylated residue
+is_a: MOD:01155 ! lipoconjugated residue
 
 [Term]
 id: MOD:00704
@@ -14542,7 +14541,7 @@ property_value: DiffMono "-18.010565" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:23
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:00705
@@ -14563,7 +14562,7 @@ property_value: MassMono "99.068414" xsd:float
 property_value: Origin "V" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0124
-is_a: MOD:00664
+is_a: MOD:00664 ! stereoisomerized residue
 
 [Term]
 id: MOD:00706
@@ -14582,8 +14581,8 @@ property_value: Origin "Y" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:401
 xref: uniprot.ptm:PTM-0008
-is_a: MOD:00919
-is_a: MOD:01888
+is_a: MOD:00919 ! modified L-tyrosine residue
+is_a: MOD:01888 ! didehydrogenated residue
 
 [Term]
 id: MOD:00707
@@ -14593,8 +14592,8 @@ subset: PSI-MOD-slim
 synonym: "HyTyr" EXACT PSI-MOD-label []
 property_value: Origin "Y" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00677
-is_a: MOD:00919
+is_a: MOD:00677 ! hydroxylated residue
+is_a: MOD:00919 ! modified L-tyrosine residue
 
 [Term]
 id: MOD:00708
@@ -14604,8 +14603,8 @@ subset: PSI-MOD-slim
 synonym: "SOxyCys" EXACT PSI-MOD-label []
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00680
-is_a: MOD:00905
+is_a: MOD:00680 ! sulfur oxygenated residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00709
@@ -14615,8 +14614,8 @@ subset: PSI-MOD-slim
 synonym: "SOxyMet" EXACT PSI-MOD-label []
 property_value: Origin "M" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00680
-is_a: MOD:00913
+is_a: MOD:00680 ! sulfur oxygenated residue
+is_a: MOD:00913 ! modified L-methionine residue
 
 [Term]
 id: MOD:00710
@@ -14625,7 +14624,7 @@ def: "A protein modification that effectively adds a proton and replaces two hyd
 comment: For N-terminal proline residues, dimethylation can effectively only be accomplished with a protonated imino group. This process accounts for both protonation and dimethylation. The alternative Me2Res process accounts only for dimethylation and not protonation.
 subset: PSI-MOD-slim
 synonym: "Me2+Res" EXACT PSI-MOD-label []
-is_a: MOD:00429
+is_a: MOD:00429 ! dimethylated residue
 
 [Term]
 id: MOD:00711
@@ -14640,7 +14639,7 @@ property_value: DiffMono "43.054227" xsd:float
 property_value: FormalCharge "1+" xsd:string
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00427
+is_a: MOD:00427 ! methylated residue
 
 [Term]
 id: MOD:00712
@@ -14650,8 +14649,8 @@ subset: PSI-MOD-slim
 synonym: "MePro" EXACT PSI-MOD-label []
 property_value: Origin "P" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00427
-is_a: MOD:00915
+is_a: MOD:00427 ! methylated residue
+is_a: MOD:00915 ! modified L-proline residue
 
 [Term]
 id: MOD:00713
@@ -14661,8 +14660,8 @@ subset: PSI-MOD-slim
 synonym: "MeGlu" EXACT PSI-MOD-label []
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00427
-is_a: MOD:00906
+is_a: MOD:00427 ! methylated residue
+is_a: MOD:00906 ! modified L-glutamic acid residue
 
 [Term]
 id: MOD:00714
@@ -14671,8 +14670,8 @@ def: "A protein modification that effectively converts a glycine residue to a me
 synonym: "MeGly" EXACT PSI-MOD-label []
 property_value: Origin "G" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00427
-is_a: MOD:00908
+is_a: MOD:00427 ! methylated residue
+is_a: MOD:00908 ! modified glycine residue
 
 [Term]
 id: MOD:00715
@@ -14681,8 +14680,8 @@ def: "A protein modification that effectively converts an L-isoleucine residue t
 synonym: "MeIle" EXACT PSI-MOD-label []
 property_value: Origin "I" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00427
-is_a: MOD:00910
+is_a: MOD:00427 ! methylated residue
+is_a: MOD:00910 ! modified L-isoleucine residue
 
 [Term]
 id: MOD:00716
@@ -14693,8 +14692,8 @@ synonym: "MeMet" EXACT PSI-MOD-label []
 property_value: Origin "M" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00427
-is_a: MOD:00913
+is_a: MOD:00427 ! methylated residue
+is_a: MOD:00913 ! modified L-methionine residue
 
 [Term]
 id: MOD:00717
@@ -14704,8 +14703,8 @@ subset: PSI-MOD-slim
 synonym: "MePhe" EXACT PSI-MOD-label []
 property_value: Origin "F" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00427
-is_a: MOD:00914
+is_a: MOD:00427 ! methylated residue
+is_a: MOD:00914 ! modified L-phenylalanine residue
 
 [Term]
 id: MOD:00718
@@ -14715,8 +14714,8 @@ synonym: "MeTyr" EXACT PSI-MOD-label []
 property_value: Origin "Y" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00427
-is_a: MOD:00919
+is_a: MOD:00427 ! methylated residue
+is_a: MOD:00919 ! modified L-tyrosine residue
 
 [Term]
 id: MOD:00719
@@ -14744,8 +14743,8 @@ property_value: Origin "M" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:35
 xref: uniprot.ptm:PTM-0469
-is_a: MOD:00709
-is_a: MOD:01854
+is_a: MOD:00709 ! sulfur oxygenated L-methionine
+is_a: MOD:01854 ! sulfur monooxygenated residue
 
 [Term]
 id: MOD:00720
@@ -14765,7 +14764,7 @@ property_value: MassMono "147.035400" xsd:float
 property_value: Origin "M" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0480
-is_a: MOD:00719
+is_a: MOD:00719 ! L-methionine sulfoxide
 
 [Term]
 id: MOD:00721
@@ -14782,7 +14781,7 @@ property_value: MassMono "147.035400" xsd:float
 property_value: Origin "M" xsd:string
 property_value: Source "artifact" xsd:string
 xref: uniprot.ptm:PTM-0481
-is_a: MOD:00719
+is_a: MOD:00719 ! L-methionine sulfoxide
 
 [Term]
 id: MOD:00722
@@ -14800,8 +14799,8 @@ property_value: MassMono "142.074228" xsd:float
 property_value: Origin "Q" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:34
-is_a: MOD:00599
-is_a: MOD:00659
+is_a: MOD:00599 ! monomethylated residue
+is_a: MOD:00659 ! methylated glutamine
 
 [Term]
 id: MOD:00723
@@ -14817,8 +14816,8 @@ property_value: MassAvg "171.22" xsd:float
 property_value: MassMono "171.113353" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00408
-is_a: MOD:00912
+is_a: MOD:00408 ! mono N-acetylated residue
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:00724
@@ -14837,15 +14836,15 @@ property_value: MassMono "151.074562" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:34
-is_a: MOD:00599
-is_a: MOD:00602
-is_a: MOD:00661
+is_a: MOD:00599 ! monomethylated residue
+is_a: MOD:00602 ! N-methylated residue
+is_a: MOD:00661 ! methylated histidine
 
 [Term]
 id: MOD:00725
 name: complex glycosylation
 def: "A protein modification that effectively replaces a hydrogen atom of an amino acid residue or of a modifying group with a carbohydrate-like group linked through a glycosidic bond." [PubMed:18688235]
-is_a: MOD:00693
+is_a: MOD:00693 ! glycosylated residue
 
 [Term]
 id: MOD:00726
@@ -14855,7 +14854,7 @@ synonym: "Glc" EXACT PSI-MOD-label []
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 replaced_by: MOD:00433
-is_a: MOD:00693
+is_a: MOD:00693 ! glycosylated residue
 
 [Term]
 id: MOD:00727
@@ -14864,7 +14863,7 @@ def: "A protein modification that effectively replaces a hydrogen atom of an ami
 synonym: "Man" EXACT PSI-MOD-label []
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00693
+is_a: MOD:00693 ! glycosylated residue
 
 [Term]
 id: MOD:00728
@@ -14873,7 +14872,7 @@ def: "A protein modification that effectively replaces a hydrogen atom of an ami
 synonym: "Gal" EXACT PSI-MOD-label []
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00693
+is_a: MOD:00693 ! glycosylated residue
 
 [Term]
 id: MOD:00729
@@ -14888,7 +14887,7 @@ property_value: DiffFormula "C 5 H 8 O 4" xsd:string
 property_value: DiffMono "132.042259" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00693
+is_a: MOD:00693 ! glycosylated residue
 
 [Term]
 id: MOD:00730
@@ -14900,7 +14899,7 @@ property_value: DiffFormula "C 5 H 8 O 4" xsd:string
 property_value: DiffMono "132.042259" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00729
+is_a: MOD:00729 ! pentosylated residue
 
 [Term]
 id: MOD:00731
@@ -14912,7 +14911,7 @@ property_value: DiffFormula "C 5 H 8 O 4" xsd:string
 property_value: DiffMono "132.042259" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00729
+is_a: MOD:00729 ! pentosylated residue
 
 [Term]
 id: MOD:00732
@@ -14924,7 +14923,7 @@ property_value: DiffFormula "C 5 H 8 O 4" xsd:string
 property_value: DiffMono "132.042259" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00729
+is_a: MOD:00729 ! pentosylated residue
 
 [Term]
 id: MOD:00733
@@ -14935,7 +14934,7 @@ property_value: DiffAvg "203.19" xsd:float
 property_value: DiffFormula "C 8 H 13 N 1 O 5" xsd:string
 property_value: DiffMono "203.079373" xsd:float
 property_value: Origin "X" xsd:string
-is_a: MOD:00436
+is_a: MOD:00436 ! N-acetylhexosaminylated residue
 
 [Term]
 id: MOD:00734
@@ -14948,7 +14947,7 @@ property_value: DiffAvg "203.19" xsd:float
 property_value: DiffFormula "C 8 H 13 N 1 O 5" xsd:string
 property_value: DiffMono "203.079373" xsd:float
 property_value: Origin "X" xsd:string
-is_a: MOD:00436
+is_a: MOD:00436 ! N-acetylhexosaminylated residue
 
 [Term]
 id: MOD:00735
@@ -14960,7 +14959,7 @@ property_value: DiffFormula "C 6 H 8 O 6" xsd:string
 property_value: DiffMono "176.032088" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00693
+is_a: MOD:00693 ! glycosylated residue
 
 [Term]
 id: MOD:00736
@@ -14976,7 +14975,7 @@ property_value: DiffMono "146.057909" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 xref: GNO:G02438LG
-is_a: MOD:00693
+is_a: MOD:00693 ! glycosylated residue
 
 [Term]
 id: MOD:00737
@@ -14991,43 +14990,43 @@ property_value: DiffMono "291.095417" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 xref: GNO:G76685HR
-is_a: MOD:00693
+is_a: MOD:00693 ! glycosylated residue
 
 [Term]
 id: MOD:00738
 name: iron containing modified residue
 def: "A protein modification that effectively substitutes an iron atom or a cluster containing iron for hydrogen atoms, or that coordinates an iron ion." [PubMed:18688235]
 synonym: "FeRes" EXACT PSI-MOD-label []
-is_a: MOD:00698
+is_a: MOD:00698 ! metal or metal cluster containing modified residue
 
 [Term]
 id: MOD:00739
 name: iron-sulfur cluster containing modification
 def: "A protein modification that effectively substitutes a cluster of iron and sulfur atoms for hydrogen atoms." [PubMed:18688235]
 synonym: "FeSRes" EXACT PSI-MOD-label []
-is_a: MOD:00738
-is_a: MOD:00860
+is_a: MOD:00738 ! iron containing modified residue
+is_a: MOD:00860 ! sulfur containing modified residue
 
 [Term]
 id: MOD:00740
 name: manganese containing modified residue
 def: "A protein modification that effectively substitutes a manganese atom or a cluster containing manganese for hydrogen atoms, or that coordinates a manganese ion." [PubMed:18688235]
 synonym: "MnRes" EXACT PSI-MOD-label []
-is_a: MOD:00698
+is_a: MOD:00698 ! metal or metal cluster containing modified residue
 
 [Term]
 id: MOD:00741
 name: nickel containing modified residue
 def: "A protein modification that effectively substitutes a nickel atom or a cluster containing nickel for hydrogen atoms, or that coordinates a nickel ion." [PubMed:18688235]
 synonym: "NiRes" EXACT PSI-MOD-label []
-is_a: MOD:00698
+is_a: MOD:00698 ! metal or metal cluster containing modified residue
 
 [Term]
 id: MOD:00742
 name: copper containing modified residue
 def: "A protein modification that effectively substitutes a copper atom or a cluster containing copper for hydrogen atoms, or that coordinates a copper ion." [PubMed:18688235]
 synonym: "CuRes" EXACT PSI-MOD-label []
-is_a: MOD:00698
+is_a: MOD:00698 ! metal or metal cluster containing modified residue
 
 [Term]
 id: MOD:00743
@@ -15035,7 +15034,7 @@ name: molybdenum containing modified residue
 def: "A protein modification that effectively substitutes a molybdenum atom or a cluster containing molybdenum for hydrogen atoms, or that coordinates a molybdenum ion." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "MoRes" EXACT PSI-MOD-label []
-is_a: MOD:00698
+is_a: MOD:00698 ! metal or metal cluster containing modified residue
 
 [Term]
 id: MOD:00744
@@ -15043,8 +15042,8 @@ name: molybdenum pterin containing modification
 def: "A protein modification containing a molybdenum atom in a pterin ring system." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "MoPterRes" EXACT PSI-MOD-label []
-is_a: MOD:00743
-is_a: MOD:00748
+is_a: MOD:00743 ! molybdenum containing modified residue
+is_a: MOD:00748 ! pterin modified residue
 
 [Term]
 id: MOD:00745
@@ -15052,14 +15051,14 @@ name: selenium containing residue
 def: "A protein modification that effectively substitutes a selenium atom or a cluster containing selenium for hydrogen atoms." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "SeRes" EXACT PSI-MOD-label []
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:00746
 name: tungsten containing modified residue
 def: "A protein modification that effectively substitutes a tungsten atom or a cluster containing tungsten for hydrogen atoms, or that coordinates a tungsten ion." [PubMed:18688235]
 synonym: "WRes" EXACT PSI-MOD-label []
-is_a: MOD:00698
+is_a: MOD:00698 ! metal or metal cluster containing modified residue
 
 [Term]
 id: MOD:00747
@@ -15067,7 +15066,7 @@ name: sodium containing modified residue
 def: "A protein modification that effectively substitutes a sodium atom for a hydrogen atom." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "NaRes" EXACT PSI-MOD-label []
-is_a: MOD:00698
+is_a: MOD:00698 ! metal or metal cluster containing modified residue
 
 [Term]
 id: MOD:00748
@@ -15075,7 +15074,7 @@ name: pterin modified residue
 def: "A protein modification that effectively results from forming an adduct with a compound containing a pterin group." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "PterRes" EXACT PSI-MOD-label []
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:00749
@@ -15083,21 +15082,21 @@ name: sulfur substitution for oxygen
 def: "A protein modification that effectively substitutes a sulfur atom for an oxygen atom." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "S(O)Res" EXACT PSI-MOD-label []
-is_a: MOD:00860
+is_a: MOD:00860 ! sulfur containing modified residue
 
 [Term]
 id: MOD:00750
 name: deoxyribonucleic acid linked residue
 def: "A protein modification that effectively crosslinks an amino acid residue and the 3'- or 5'-end of DNA through a phosphodiester bond." [PubMed:18688235]
 synonym: "DNARes" EXACT PSI-MOD-label []
-is_a: MOD:00701
+is_a: MOD:00701 ! nucleotide or nucleic acid modified residue
 
 [Term]
 id: MOD:00751
 name: ribonucleic acid linked residue
 def: "a protein modification" [PubMed:18688235]
 synonym: "RNARes" EXACT PSI-MOD-label []
-is_a: MOD:00701
+is_a: MOD:00701 ! nucleotide or nucleic acid modified residue
 
 [Term]
 id: MOD:00752
@@ -15112,7 +15111,7 @@ property_value: DiffFormula "C 15 H 21 N 5 O 13 P 2" xsd:string
 property_value: DiffMono "541.061109" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:02087
+is_a: MOD:02087 ! adenosine diphosphoribosyl (ADP-ribosyl) modified residue
 
 [Term]
 id: MOD:00753
@@ -15120,7 +15119,7 @@ name: chlorinated residue
 def: "A protein modification that effectively substitutes a chlorine atom for a hydrogen atom." [PubMed:18688235]
 synonym: "ClRes" EXACT PSI-MOD-label []
 property_value: Origin "X" xsd:string
-is_a: MOD:00694
+is_a: MOD:00694 ! halogen containing residue
 
 [Term]
 id: MOD:00754
@@ -15128,7 +15127,7 @@ name: brominated residue
 def: "A protein modification that effectively substitutes a bromine atom for a hydrogen atom." [PubMed:18688235]
 synonym: "BrRes" EXACT PSI-MOD-label []
 property_value: Origin "X" xsd:string
-is_a: MOD:00694
+is_a: MOD:00694 ! halogen containing residue
 
 [Term]
 id: MOD:00755
@@ -15137,7 +15136,7 @@ def: "A protein modification that effectively substitutes an iodine atom of a re
 subset: PSI-MOD-slim
 synonym: "IRes" EXACT PSI-MOD-label []
 property_value: Origin "X" xsd:string
-is_a: MOD:00694
+is_a: MOD:00694 ! halogen containing residue
 
 [Term]
 id: MOD:00756
@@ -15157,8 +15156,8 @@ property_value: MassMono "115.063329" xsd:float
 property_value: Origin "V" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0111
-is_a: MOD:00425
-is_a: MOD:00664
+is_a: MOD:00425 ! monohydroxylated residue
+is_a: MOD:00664 ! stereoisomerized residue
 
 [Term]
 id: MOD:00757
@@ -15181,7 +15180,7 @@ property_value: MassMono "275.100502" xsd:float
 property_value: Origin "P" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0558
-is_a: MOD:00915
+is_a: MOD:00915 ! modified L-proline residue
 
 [Term]
 id: MOD:00758
@@ -15206,7 +15205,7 @@ property_value: MassMono "316.127051" xsd:float
 property_value: Origin "P" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0578
-is_a: MOD:01677
+is_a: MOD:01677 ! O4-(N-acetylamino)hexosyl-L-hydroxyproline
 
 [Term]
 id: MOD:00759
@@ -15224,8 +15223,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:307
 xref: GNO:G59937CP
-is_a: MOD:00725
-is_a: MOD:00160
+is_a: MOD:00725 ! complex glycosylation
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:00760
@@ -15243,8 +15242,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:311
 xref: GNO:G10486CT
-is_a: MOD:00725
-is_a: MOD:00160
+is_a: MOD:00725 ! complex glycosylation
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:00761
@@ -15257,7 +15256,7 @@ property_value: DiffMono "162.052823" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 xref: GNO:G81399MY
-is_a: MOD:00434
+is_a: MOD:00434 ! hexosylated residue
 
 [Term]
 id: MOD:00762
@@ -15275,8 +15274,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:309
 xref: GNO:G35029YA
-is_a: MOD:00725
-is_a: MOD:00160
+is_a: MOD:00725 ! complex glycosylation
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:00763
@@ -15294,15 +15293,15 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:310
 xref: GNO:G72787SB
-is_a: MOD:00725
-is_a: MOD:00160
+is_a: MOD:00725 ! complex glycosylation
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:00764
 name: glycoconjugated residue
 def: "A protein modification that effectively results from forming an adduct with a carbohydrate-like group either through enzymatic formation of a glycosidic bond, or through non-enzymatic glycation formation of a Schiff-base or an Amadori ketosamine residue adduct." [PubMed:18688235, PubMed:3743566]
 subset: PSI-MOD-slim
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:00765
@@ -15336,8 +15335,8 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:312
 xref: uniprot.ptm:PTM-0415
-is_a: MOD:00905
-is_a: MOD:01862
+is_a: MOD:00905 ! modified L-cysteine residue
+is_a: MOD:01862 ! disulfide conjugated residue
 
 [Term]
 id: MOD:00766
@@ -15359,7 +15358,7 @@ id: MOD:00767
 name: glycated residue
 def: "A modification produced in a non-enzymatic reaction between a carbohydrate carbonyl group (C1 of aldohexose or C2 of fructose) and a protein amino group to form a Schiff-base or an Amadori ketosamine residue adduct." [PubMed:18688235]
 property_value: Source "artifact" xsd:string
-is_a: MOD:00764
+is_a: MOD:00764 ! glycoconjugated residue
 
 [Term]
 id: MOD:00768
@@ -15374,49 +15373,49 @@ property_value: MassAvg "83.09" xsd:float
 property_value: MassMono "83.037114" xsd:float
 property_value: Origin "M" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00431
+is_a: MOD:00431 ! modified residue with a secondary neutral loss
 
 [Term]
 id: MOD:00769
 name: residues isobaric at 71.0-71.1 Da
 def: "Natural or modified residues with a mass of 71.0-71.1 Da." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00616
+is_a: MOD:00616 ! residues isobaric at a resolution below 0.1 Da
 
 [Term]
 id: MOD:00770
 name: residues isobaric at a resolution below 0.01 Da
 def: "Natural or modified residues that are isobaric at a resolution below 0.01 Da." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00616
+is_a: MOD:00616 ! residues isobaric at a resolution below 0.1 Da
 
 [Term]
 id: MOD:00771
 name: residues isobaric at 166.98-167.00 Da
 def: "Natural or modified residues with a mass of 166.98-167.00 Da." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00770
+is_a: MOD:00770 ! residues isobaric at a resolution below 0.01 Da
 
 [Term]
 id: MOD:00772
 name: vanadium containing modified residue
 def: "A protein modification that effectively substitutes a vanadium atom or a cluster containing vanadium for hydrogen atoms, or that coordinates a vanadium ion." [PubMed:18688235]
 synonym: "VRes" EXACT PSI-MOD-label []
-is_a: MOD:00698
+is_a: MOD:00698 ! metal or metal cluster containing modified residue
 
 [Term]
 id: MOD:00773
 name: residues isobaric at 181.00-181.02 Da
 def: "Natural or modified residues with a mass of 181.00-181.02 Da." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00770
+is_a: MOD:00770 ! residues isobaric at a resolution below 0.01 Da
 
 [Term]
 id: MOD:00774
 name: residues isobaric at 243.02-243.03 Da
 def: "Natural or modified residues with a mass of 243.02-243.03 Da." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00770
+is_a: MOD:00770 ! residues isobaric at a resolution below 0.01 Da
 
 [Term]
 id: MOD:00775
@@ -15434,8 +15433,8 @@ property_value: MassMono "114.042927" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:348
-is_a: MOD:00909
-is_a: MOD:02088
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:02088 ! natural, standard, encoded residue substitution
 
 [Term]
 id: MOD:00776
@@ -15454,22 +15453,22 @@ property_value: MassMono "115.026943" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:349
-is_a: MOD:00909
-is_a: MOD:02088
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:02088 ! natural, standard, encoded residue substitution
 
 [Term]
 id: MOD:00777
 name: residues isobaric at 182.96-182.98 Da
 def: "Natural or modified residues with a mass of 182.96-182.98 Da." [PubMed:18688235]
-is_a: MOD:00770
-is_a: MOD:00778
+is_a: MOD:00770 ! residues isobaric at a resolution below 0.01 Da
+is_a: MOD:00778 ! residues isobaric at 182.9-183.0 Da
 
 [Term]
 id: MOD:00778
 name: residues isobaric at 182.9-183.0 Da
 def: "Natural or modified residues with a mass of 182.9-183.0 Da." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00616
+is_a: MOD:00616 ! residues isobaric at a resolution below 0.1 Da
 
 [Term]
 id: MOD:00779
@@ -15501,8 +15500,8 @@ property_value: MassMono "156.053492" xsd:float
 property_value: Origin "N" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00903
-is_a: MOD:01458
+is_a: MOD:00903 ! modified L-asparagine residue
+is_a: MOD:01458 ! alpha-amino acetylated residue
 
 [Term]
 id: MOD:00781
@@ -15519,8 +15518,8 @@ property_value: MassMono "179.069477" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00909
-is_a: MOD:01458
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:01458 ! alpha-amino acetylated residue
 
 [Term]
 id: MOD:00782
@@ -15537,8 +15536,8 @@ property_value: MassMono "156.102454" xsd:float
 property_value: Origin "L" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00911
-is_a: MOD:01458
+is_a: MOD:00911 ! modified L-leucine residue
+is_a: MOD:01458 ! alpha-amino acetylated residue
 
 [Term]
 id: MOD:00783
@@ -15558,8 +15557,8 @@ property_value: Origin "R" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:36
 xref: uniprot.ptm:PTM-0341
-is_a: MOD:00429
-is_a: MOD:00658
+is_a: MOD:00429 ! dimethylated residue
+is_a: MOD:00658 ! methylated arginine
 
 [Term]
 id: MOD:00784
@@ -15576,8 +15575,8 @@ property_value: MassMono "189.078979" xsd:float
 property_value: Origin "F" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00914
-is_a: MOD:01458
+is_a: MOD:00914 ! modified L-phenylalanine residue
+is_a: MOD:01458 ! alpha-amino acetylated residue
 
 [Term]
 id: MOD:00785
@@ -15594,8 +15593,8 @@ property_value: MassMono "228.089878" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00918
-is_a: MOD:01458
+is_a: MOD:00918 ! modified L-tryptophan residue
+is_a: MOD:01458 ! alpha-amino acetylated residue
 
 [Term]
 id: MOD:00786
@@ -15603,7 +15602,7 @@ name: deuterium substituted residue
 def: "A protein modification that effectively substitutes one or more (2)H deuterium atoms for (1)H protium atoms." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "D(H)Res" EXACT PSI-MOD-label []
-is_a: MOD:00839
+is_a: MOD:00839 ! (2)H deuterium labeled residue
 
 [Term]
 id: MOD:00787
@@ -15620,9 +15619,9 @@ property_value: MassMono "251.092259" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:362
-is_a: MOD:00848
-is_a: MOD:00861
-is_a: MOD:00916
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00861 ! phosphorus containing modified residue
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:00788
@@ -15639,9 +15638,9 @@ property_value: MassMono "285.076609" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:363
-is_a: MOD:00848
-is_a: MOD:00861
-is_a: MOD:00919
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00861 ! phosphorus containing modified residue
+is_a: MOD:00919 ! modified L-tyrosine residue
 
 [Term]
 id: MOD:00789
@@ -15655,7 +15654,7 @@ property_value: DiffMono "111.041593" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:364
-is_a: MOD:01428
+is_a: MOD:01428 ! (13)C isotope tagged reagent
 
 [Term]
 id: MOD:00790
@@ -15669,7 +15668,7 @@ property_value: DiffMono "105.021464" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:365
-is_a: MOD:01426
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
 
 [Term]
 id: MOD:00791
@@ -15687,8 +15686,8 @@ property_value: MassMono "131.046839" xsd:float
 property_value: Origin "Q" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:366
-relationship: derives_from MOD:00685
-is_a: MOD:00852
+relationship: derives_from MOD:00685 ! deamidated L-glutamine
+is_a: MOD:00852 ! 1x(18)O labeled deamidated residue
 
 [Term]
 id: MOD:00792
@@ -15696,7 +15695,7 @@ name: deuterium monosubstituted residue
 def: "A protein modification that effectively substitutes one (2)H deuterium atom for one (1)H protium atom." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "D(H)1Res" EXACT PSI-MOD-label []
-is_a: MOD:00786
+is_a: MOD:00786 ! deuterium substituted residue
 
 [Term]
 id: MOD:00793
@@ -15726,8 +15725,8 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:368
 xref: uniprot.ptm:PTM-0468
-is_a: MOD:00905
-is_a: MOD:01168
+is_a: MOD:00905 ! modified L-cysteine residue
+is_a: MOD:01168 ! dehydroalanine
 
 [Term]
 id: MOD:00794
@@ -15763,7 +15762,7 @@ property_value: MassMono "189.045964" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:371
-is_a: MOD:00905
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00796
@@ -15784,7 +15783,7 @@ property_value: MassMono "114.079313" xsd:float
 property_value: Origin "R" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:372
-is_a: MOD:00902
+is_a: MOD:00902 ! modified L-arginine residue
 
 [Term]
 id: MOD:00797
@@ -15809,8 +15808,8 @@ property_value: MassMono "270.991559" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0424
-is_a: MOD:00861
-is_a: MOD:00905
+is_a: MOD:00861 ! phosphorus containing modified residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00798
@@ -15826,7 +15825,7 @@ property_value: MassAvg "102.13" xsd:float
 property_value: MassMono "102.001360" xsd:float
 property_value: Origin "C" xsd:string
 xref: Unimod:374
-is_a: MOD:00905
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00799
@@ -15848,9 +15847,9 @@ property_value: MassMono "265.062008" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: uniprot.ptm:PTM-0624
-is_a: MOD:00426
-is_a: MOD:00476
-is_a: MOD:00905
+is_a: MOD:00426 ! S-glycosylated residue
+is_a: MOD:00476 ! monogalactosylated residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00800
@@ -15868,10 +15867,10 @@ property_value: MassAvg "1172.80" xsd:float
 property_value: MassMono "1172.316610" xsd:float
 property_value: Origin "C, H" xsd:string
 property_value: Source "hypothetical" xsd:string
-is_a: MOD:00739
-is_a: MOD:00772
-is_a: MOD:02067
-is_a: MOD:02070
+is_a: MOD:00739 ! iron-sulfur cluster containing modification
+is_a: MOD:00772 ! vanadium containing modified residue
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
+is_a: MOD:02070 ! metal or metal cluster coordinated L-histidine residue
 
 [Term]
 id: MOD:00801
@@ -15890,9 +15889,9 @@ property_value: MassAvg "1177.70" xsd:float
 property_value: MassMono "1177.308685" xsd:float
 property_value: Origin "C, H" xsd:string
 property_value: Source "hypothetical" xsd:string
-is_a: MOD:00739
-is_a: MOD:02067
-is_a: MOD:02070
+is_a: MOD:00739 ! iron-sulfur cluster containing modification
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
+is_a: MOD:02070 ! metal or metal cluster coordinated L-histidine residue
 
 [Term]
 id: MOD:00802
@@ -15919,8 +15918,8 @@ property_value: MassAvg "254.10" xsd:float
 property_value: MassMono "253.998180" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00772
-is_a: MOD:02070
+is_a: MOD:00772 ! vanadium containing modified residue
+is_a: MOD:02070 ! metal or metal cluster coordinated L-histidine residue
 
 [Term]
 id: MOD:00803
@@ -15942,8 +15941,8 @@ property_value: MassMono "264.056863" xsd:float
 property_value: Origin "C, Y" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0020
-is_a: MOD:02058
-is_a: MOD:01993
+is_a: MOD:02058 ! crosslinked L-tyrosine residue
+is_a: MOD:01993 ! beta-carbon thioether crosslinked residues
 
 [Term]
 id: MOD:00804
@@ -15966,8 +15965,8 @@ property_value: MassMono "249.084852" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0573
-is_a: MOD:00002
-is_a: MOD:00433
+is_a: MOD:00002 ! O-glycosyl-L-serine
+is_a: MOD:00433 ! monoglucosylated residue
 
 [Term]
 id: MOD:00805
@@ -15995,8 +15994,8 @@ property_value: MassMono "290.111401" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0580
-is_a: MOD:00448
-is_a: MOD:01675
+is_a: MOD:00448 ! mono-N-acetylaminoglucosylated residue
+is_a: MOD:01675 ! O-(N-acetylamino)hexosyl-L-serine
 
 [Term]
 id: MOD:00806
@@ -16024,8 +16023,8 @@ property_value: MassMono "304.127051" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0582
-is_a: MOD:00448
-is_a: MOD:01676
+is_a: MOD:00448 ! mono-N-acetylaminoglucosylated residue
+is_a: MOD:01676 ! O-(N-acetylamino)hexosyl-L-threonine
 
 [Term]
 id: MOD:00807
@@ -16049,9 +16048,9 @@ property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:385
 xref: uniprot.ptm:PTM-0266
-is_a: MOD:00916
-is_a: MOD:01154
-is_a: MOD:01160
+is_a: MOD:00916 ! modified L-serine residue
+is_a: MOD:01154 ! pyruvic acid
+is_a: MOD:01160 ! deaminated residue
 
 [Term]
 id: MOD:00808
@@ -16073,8 +16072,8 @@ property_value: MassMono "249.084852" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0560
-is_a: MOD:00002
-is_a: MOD:00476
+is_a: MOD:00002 ! O-glycosyl-L-serine
+is_a: MOD:00476 ! monogalactosylated residue
 
 [Term]
 id: MOD:00809
@@ -16096,8 +16095,8 @@ property_value: MassMono "263.100502" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0562
-is_a: MOD:00476
-is_a: MOD:01348
+is_a: MOD:00476 ! monogalactosylated residue
+is_a: MOD:01348 ! O-hexosylated threonine
 
 [Term]
 id: MOD:00810
@@ -16120,8 +16119,8 @@ property_value: MassMono "249.084852" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0588
-is_a: MOD:00002
-is_a: MOD:00595
+is_a: MOD:00002 ! O-glycosyl-L-serine
+is_a: MOD:00595 ! monomannosylated residue
 
 [Term]
 id: MOD:00811
@@ -16143,8 +16142,8 @@ property_value: MassMono "263.100502" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0591
-is_a: MOD:00595
-is_a: MOD:01348
+is_a: MOD:00595 ! monomannosylated residue
+is_a: MOD:01348 ! O-hexosylated threonine
 
 [Term]
 id: MOD:00812
@@ -16171,8 +16170,8 @@ property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:295
 xref: uniprot.ptm:PTM-0550
-is_a: MOD:00002
-is_a: MOD:00614
+is_a: MOD:00002 ! O-glycosyl-L-serine
+is_a: MOD:00614 ! fucosylated residue
 
 [Term]
 id: MOD:00813
@@ -16198,8 +16197,8 @@ property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:295
 xref: uniprot.ptm:PTM-0552
-is_a: MOD:00005
-is_a: MOD:00614
+is_a: MOD:00005 ! O-glycosyl-L-threonine
+is_a: MOD:00614 ! fucosylated residue
 
 [Term]
 id: MOD:00814
@@ -16222,7 +16221,7 @@ property_value: MassMono "219.074287" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
 xref: uniprot.ptm:PTM-0598
-is_a: MOD:00002
+is_a: MOD:00002 ! O-glycosyl-L-serine
 
 [Term]
 id: MOD:00815
@@ -16259,8 +16258,8 @@ property_value: MassMono "369.270150" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0283
-is_a: MOD:02005
-is_a: MOD:02006
+is_a: MOD:02005 ! S-acylated L-cysteine
+is_a: MOD:02006 ! S-stearoylated residue
 
 [Term]
 id: MOD:00817
@@ -16280,8 +16279,8 @@ property_value: MassMono "322.204513" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0026
-is_a: MOD:00601
-is_a: MOD:01115
+is_a: MOD:00601 ! cyclized residue
+is_a: MOD:01115 ! isoprenylated tryptophan
 
 [Term]
 id: MOD:00818
@@ -16299,9 +16298,9 @@ property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: Unimod:394
 xref: uniprot.ptm:PTM-0139
-is_a: MOD:00764
-is_a: MOD:00861
-is_a: MOD:01155
+is_a: MOD:00764 ! glycoconjugated residue
+is_a: MOD:00861 ! phosphorus containing modified residue
+is_a: MOD:01155 ! lipoconjugated residue
 
 [Term]
 id: MOD:00819
@@ -16328,7 +16327,7 @@ property_value: MassAvg "85.11" xsd:float
 property_value: MassMono "85.052764" xsd:float
 property_value: Origin "E" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00906
+is_a: MOD:00906 ! modified L-glutamic acid residue
 
 [Term]
 id: MOD:00820
@@ -16352,9 +16351,9 @@ property_value: MassAvg "108.10" xsd:float
 property_value: MassMono "108.032363" xsd:float
 property_value: Origin "D, G" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:02043
-is_a: MOD:02047
-is_a: MOD:01882
+is_a: MOD:02043 ! crosslinked L-aspartic acid residue
+is_a: MOD:02047 ! crosslinked glycine residue
+is_a: MOD:01882 ! 5-imidazolinone ring crosslinked residues (Gly)
 
 [Term]
 id: MOD:00821
@@ -16376,9 +16375,9 @@ property_value: MassMono "173.038474" xsd:float
 property_value: Origin "A, C" xsd:string
 property_value: Source "hypothetical" xsd:string
 property_value: TermSpec "C-term" xsd:string
-is_a: MOD:00395
-is_a: MOD:02040
-is_a: MOD:00954
+is_a: MOD:00395 ! thioester crosslinked residues
+is_a: MOD:02040 ! crosslinked L-alanine residue
+is_a: MOD:00954 ! crosslinked residues with loss of water
 
 [Term]
 id: MOD:00822
@@ -16400,9 +16399,9 @@ property_value: MassMono "215.085424" xsd:float
 property_value: Origin "C, L" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
-is_a: MOD:00395
-is_a: MOD:02050
-is_a: MOD:00954
+is_a: MOD:00395 ! thioester crosslinked residues
+is_a: MOD:02050 ! crosslinked L-leucine residue
+is_a: MOD:00954 ! crosslinked residues with loss of water
 
 [Term]
 id: MOD:00823
@@ -16424,9 +16423,9 @@ property_value: MassMono "233.041845" xsd:float
 property_value: Origin "C, M" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
-is_a: MOD:00395
-is_a: MOD:02052
-is_a: MOD:00954
+is_a: MOD:00395 ! thioester crosslinked residues
+is_a: MOD:02052 ! crosslinked L-methionine residue
+is_a: MOD:00954 ! crosslinked residues with loss of water
 
 [Term]
 id: MOD:00824
@@ -16451,8 +16450,8 @@ property_value: Origin "Y" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:400
 xref: uniprot.ptm:PTM-0647
-is_a: MOD:00919
-is_a: MOD:01168
+is_a: MOD:00919 ! modified L-tyrosine residue
+is_a: MOD:01168 ! dehydroalanine
 
 [Term]
 id: MOD:00825
@@ -16474,9 +16473,9 @@ property_value: MassMono "249.069774" xsd:float
 property_value: Origin "C, F" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
-is_a: MOD:00395
-is_a: MOD:02053
-is_a: MOD:00954
+is_a: MOD:00395 ! thioester crosslinked residues
+is_a: MOD:02053 ! crosslinked L-phenylalanine residue
+is_a: MOD:00954 ! crosslinked residues with loss of water
 
 [Term]
 id: MOD:00826
@@ -16498,9 +16497,9 @@ property_value: MassMono "203.049038" xsd:float
 property_value: Origin "C, T" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
-is_a: MOD:00395
-is_a: MOD:02056
-is_a: MOD:00954
+is_a: MOD:00395 ! thioester crosslinked residues
+is_a: MOD:02056 ! crosslinked L-threonine residue
+is_a: MOD:00954 ! crosslinked residues with loss of water
 
 [Term]
 id: MOD:00827
@@ -16522,9 +16521,9 @@ property_value: MassMono "265.064688" xsd:float
 property_value: Origin "C, Y" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
-is_a: MOD:00395
-is_a: MOD:02058
-is_a: MOD:00954
+is_a: MOD:00395 ! thioester crosslinked residues
+is_a: MOD:02058 ! crosslinked L-tyrosine residue
+is_a: MOD:00954 ! crosslinked residues with loss of water
 
 [Term]
 id: MOD:00828
@@ -16546,9 +16545,9 @@ property_value: MassMono "288.080673" xsd:float
 property_value: Origin "C, W" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
-is_a: MOD:00395
-is_a: MOD:02057
-is_a: MOD:00954
+is_a: MOD:00395 ! thioester crosslinked residues
+is_a: MOD:02057 ! crosslinked L-tryptophan residue
+is_a: MOD:00954 ! crosslinked residues with loss of water
 
 [Term]
 id: MOD:00829
@@ -16570,10 +16569,10 @@ property_value: MassMono "233.092617" xsd:float
 property_value: Origin "F, S" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
-is_a: MOD:00885
-is_a: MOD:02053
-is_a: MOD:02055
-is_a: MOD:00954
+is_a: MOD:00885 ! ester crosslinked residues
+is_a: MOD:02053 ! crosslinked L-phenylalanine residue
+is_a: MOD:02055 ! crosslinked L-serine residue
+is_a: MOD:00954 ! crosslinked residues with loss of water
 
 [Term]
 id: MOD:00830
@@ -16598,9 +16597,9 @@ property_value: Origin "P" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0219
-is_a: MOD:01417
-is_a: MOD:01462
-is_a: MOD:01680
+is_a: MOD:01417 ! monomethylated proline
+is_a: MOD:01462 ! N-methylated proline
+is_a: MOD:01680 ! alpha-amino monomethylated residue
 
 [Term]
 id: MOD:00831
@@ -16619,8 +16618,8 @@ property_value: MassMono "317.122300" xsd:float
 property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0527
-is_a: MOD:00448
-is_a: MOD:01674
+is_a: MOD:00448 ! mono-N-acetylaminoglucosylated residue
+is_a: MOD:01674 ! N4-(N-acetylamino)hexosyl-L-asparagine
 
 [Term]
 id: MOD:00832
@@ -16646,8 +16645,8 @@ property_value: MassMono "317.122300" xsd:float
 property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0512
-is_a: MOD:00563
-is_a: MOD:01674
+is_a: MOD:00563 ! mono-N-acetylaminogalactosylated residue
+is_a: MOD:01674 ! N4-(N-acetylamino)hexosyl-L-asparagine
 
 [Term]
 id: MOD:00833
@@ -16672,8 +16671,8 @@ property_value: MassMono "276.095751" xsd:float
 property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0517
-is_a: MOD:00433
-is_a: MOD:01346
+is_a: MOD:00433 ! monoglucosylated residue
+is_a: MOD:01346 ! N4-hexosylated asparagine
 
 [Term]
 id: MOD:00834
@@ -16698,7 +16697,7 @@ property_value: MassMono "274.116486" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0553
-is_a: MOD:00002
+is_a: MOD:00002 ! O-glycosyl-L-serine
 
 [Term]
 id: MOD:00835
@@ -16727,9 +16726,9 @@ property_value: MassMono "85.016378" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:401
-is_a: MOD:00916
-is_a: MOD:01169
-is_a: MOD:01888
+is_a: MOD:00916 ! modified L-serine residue
+is_a: MOD:01169 ! L-3-oxoalanine
+is_a: MOD:01888 ! didehydrogenated residue
 
 [Term]
 id: MOD:00836
@@ -16737,14 +16736,14 @@ name: deuterium disubstituted residue
 def: "A protein modification that effectively substitutes two (2)H deuterium atoms for two (1)H protium atoms." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "D(H)2Res" EXACT PSI-MOD-label []
-is_a: MOD:00786
+is_a: MOD:00786 ! deuterium substituted residue
 
 [Term]
 id: MOD:00837
 name: deuterium tetrasubstituted residue
 def: "A protein modification that effectively substitutes four (2)H deuterium atoms for four (1)H protium atoms." [PubMed:18688235]
 synonym: "D(H)4Res" EXACT PSI-MOD-label []
-is_a: MOD:00786
+is_a: MOD:00786 ! deuterium substituted residue
 
 [Term]
 id: MOD:00838
@@ -16762,77 +16761,77 @@ property_value: MassMono "116.102894" xsd:float
 property_value: Origin "L" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:262
-is_a: MOD:00585
-is_a: MOD:00911
+is_a: MOD:00585 ! deuterium trisubstituted residue
+is_a: MOD:00911 ! modified L-leucine residue
 
 [Term]
 id: MOD:00839
 name: (2)H deuterium labeled residue
 def: "A protein modification that effectively substitutes atoms of particular common isotopes with atoms of or groups containing deuteriumm, (2)H." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00702
+is_a: MOD:00702 ! isotope labeled residue
 
 [Term]
 id: MOD:00840
 name: isocyanate reagent derivatized residue
 def: "A protein modification produced by formation of an adduct with an isocyanate compound." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00841
 name: isothiocyanate reagent derivatized residue
 def: "A protein modification produced by formation of an adduct with an isothiocyanate compound." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00842
 name: (13)C labeled residue
 def: "A protein modification that effectively substitutes atoms of particular common isotopes with atoms of or groups containing (13)C." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00702
+is_a: MOD:00702 ! isotope labeled residue
 
 [Term]
 id: MOD:00843
 name: (15)N labeled residue
 def: "A protein modification that effectively substitutes atoms of particular common isotopes with atoms of or groups containing (15)N." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00702
+is_a: MOD:00702 ! isotope labeled residue
 
 [Term]
 id: MOD:00844
 name: (18)O labeled residue
 def: "A protein modification that effectively substitutes atoms of particular common isotopes with atoms of or groups containing (18)O." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00702
+is_a: MOD:00702 ! isotope labeled residue
 
 [Term]
 id: MOD:00845
 name: (18)O substituted residue
 def: "A protein modification that effectively substitutes one or more (18)O atoms for (16)O atoms." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00844
+is_a: MOD:00844 ! (18)O labeled residue
 
 [Term]
 id: MOD:00846
 name: levuglandinyl (prostaglandin H2) adduct
 def: "stub" [PubMed:18688235]
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00847
 name: (18)O disubstituted residue
 def: "A protein modification that effectively substitutes two (18)O atom for two (16)O atoms." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00845
+is_a: MOD:00845 ! (18)O substituted residue
 
 [Term]
 id: MOD:00848
 name: reagent derivatized residue
 def: "A protein modification that is produced by formation of an adduct with a particular compound used as a reagent." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:00849
@@ -16840,14 +16839,14 @@ name: potassium containing modified residue
 def: "A protein modification that effectively substitutes a potassium atom for a hydrogen atom." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "KRes" EXACT PSI-MOD-label []
-is_a: MOD:00698
+is_a: MOD:00698 ! metal or metal cluster containing modified residue
 
 [Term]
 id: MOD:00850
 name: unnatural residue
 def: "A protein modification that inserts or replaces a residue with an unnatural residue that is not considered to be derived from a natural residue by some chemical process." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:01157
+is_a: MOD:01157 ! protein modification categorized by amino acid modified
 
 [Term]
 id: MOD:00851
@@ -16856,8 +16855,8 @@ def: "A protein modification that effectively replaces a carboxamido group with
 subset: PSI-MOD-slim
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00400
-is_a: MOD:00844
+is_a: MOD:00400 ! deamidated residue
+is_a: MOD:00844 ! (18)O labeled residue
 
 [Term]
 id: MOD:00852
@@ -16870,7 +16869,7 @@ property_value: DiffMono "2.988262" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:366
-is_a: MOD:00851
+is_a: MOD:00851 ! (18)O labeled deamidated residue
 
 [Term]
 id: MOD:00853
@@ -16882,7 +16881,7 @@ property_value: DiffFormula "H -1 N -1 (16)O -1 (18)O 2" xsd:string
 property_value: DiffMono "4.992508" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00851
+is_a: MOD:00851 ! (18)O labeled deamidated residue
 
 [Term]
 id: MOD:00854
@@ -16899,8 +16898,8 @@ property_value: MassAvg "129.18" xsd:float
 property_value: MassMono "129.102239" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00912
-is_a: MOD:01699
+is_a: MOD:00912 ! modified L-lysine residue
+is_a: MOD:01699 ! protonated residue
 
 [Term]
 id: MOD:00855
@@ -16920,8 +16919,8 @@ property_value: MassMono "171.149190" xsd:float
 property_value: Origin "MOD:00854" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:37
-is_a: MOD:00430
-relationship: derives_from MOD:00854
+is_a: MOD:00430 ! trimethylated residue
+relationship: derives_from MOD:00854 ! protonated L-lysine (L-lysinium) residue
 
 [Term]
 id: MOD:00856
@@ -16938,8 +16937,8 @@ property_value: MassMono "73.052215" xsd:float
 property_value: Origin "A" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00901
-is_a: MOD:01700
+is_a: MOD:00901 ! modified L-alanine residue
+is_a: MOD:01700 ! alpha-amino protonated residue
 
 [Term]
 id: MOD:00857
@@ -16959,8 +16958,8 @@ property_value: Origin "MOD:00856" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:37
-is_a: MOD:01687
-relationship: derives_from MOD:00856
+is_a: MOD:01687 ! alpha-amino trimethylated residue
+relationship: derives_from MOD:00856 ! protonated L-alanine (L-alaninium) residue
 
 [Term]
 id: MOD:00858
@@ -16979,9 +16978,9 @@ property_value: MassMono "71.037114" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0113
-is_a: MOD:00862
-is_a: MOD:00916
-is_a: MOD:01161
+is_a: MOD:00862 ! D-alanine
+is_a: MOD:00916 ! modified L-serine residue
+is_a: MOD:01161 ! deoxygenated residue
 
 [Term]
 id: MOD:00859
@@ -16990,21 +16989,21 @@ def: "A protein modification that can be derived from different natural residues
 subset: PSI-MOD-slim
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:01157
+is_a: MOD:01157 ! protein modification categorized by amino acid modified
 
 [Term]
 id: MOD:00860
 name: sulfur containing modified residue
 def: "A protein modification that produces an amino acid residue containing an exogenous sulfur atom." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:00861
 name: phosphorus containing modified residue
 def: "A protein modification that produces an amino acid residue containing a phosphorus atom." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:00862
@@ -17019,8 +17018,8 @@ property_value: MassAvg "71.08" xsd:float
 property_value: MassMono "71.037114" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00664
-is_a: MOD:00859
+is_a: MOD:00664 ! stereoisomerized residue
+is_a: MOD:00859 ! modified residue that can arise from different natural residues
 
 [Term]
 id: MOD:00863
@@ -17039,8 +17038,8 @@ property_value: MassMono "101.047678" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0310
-is_a: MOD:00664
-is_a: MOD:00917
+is_a: MOD:00664 ! stereoisomerized residue
+is_a: MOD:00917 ! modified L-threonine residue
 
 [Term]
 id: MOD:00864
@@ -17061,9 +17060,9 @@ property_value: MassAvg "618.34" xsd:float
 property_value: MassMono "617.870280" xsd:float
 property_value: Origin "C, C, C, H" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00739
-is_a: MOD:02067
-is_a: MOD:02070
+is_a: MOD:00739 ! iron-sulfur cluster containing modification
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
+is_a: MOD:02070 ! metal or metal cluster coordinated L-histidine residue
 
 [Term]
 id: MOD:00865
@@ -17082,8 +17081,8 @@ property_value: Origin "D" xsd:string
 property_value: Source "hypothetical" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0322
-is_a: MOD:00466
-is_a: MOD:00904
+is_a: MOD:00466 ! glycosylsphingolipidinositolated residue
+is_a: MOD:00904 ! modified L-aspartic acid residue
 
 [Term]
 id: MOD:00866
@@ -17099,8 +17098,8 @@ property_value: MassMono "129.042593" xsd:float
 property_value: Origin "P" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0024
-is_a: MOD:00428
-is_a: MOD:00678
+is_a: MOD:00428 ! dihydroxylated residue
+is_a: MOD:00678 ! hydroxylated proline
 
 [Term]
 id: MOD:00867
@@ -17119,7 +17118,7 @@ property_value: MassAvg "251.17" xsd:float
 property_value: MassMono "251.947170" xsd:float
 property_value: Origin "C, C" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:01627
+is_a: MOD:01627 ! L-cysteinyl-L-selenocysteine
 
 [Term]
 id: MOD:00868
@@ -17129,7 +17128,7 @@ comment: These are produced exclusively by modification of amino acids acylated
 subset: PSI-MOD-slim
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00009
+is_a: MOD:00009 ! natural residue
 
 [Term]
 id: MOD:00869
@@ -17153,8 +17152,8 @@ property_value: MassMono "71.037114" xsd:float
 property_value: Origin "D" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0314
-is_a: MOD:00904
-is_a: MOD:02088
+is_a: MOD:00904 ! modified L-aspartic acid residue
+is_a: MOD:02088 ! natural, standard, encoded residue substitution
 
 [Term]
 id: MOD:00870
@@ -17171,7 +17170,7 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:411
-is_a: MOD:00840
+is_a: MOD:00840 ! isocyanate reagent derivatized residue
 
 [Term]
 id: MOD:00871
@@ -17188,8 +17187,8 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:412
-relationship: derives_from MOD:00870
-is_a: MOD:01431
+relationship: derives_from MOD:00870 ! phenyl isocyanate derivatized residue
+is_a: MOD:01431 ! (2)H deuterium tagged reagent
 
 [Term]
 id: MOD:00872
@@ -17225,7 +17224,7 @@ property_value: MassMono "387.127779" xsd:float
 property_value: Origin "E" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:451
-is_a: MOD:00207
+is_a: MOD:00207 ! L-isoglutamyl-polyglutamic acid
 
 [Term]
 id: MOD:00874
@@ -17244,7 +17243,7 @@ property_value: MassMono "516.170372" xsd:float
 property_value: Origin "E" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:452
-is_a: MOD:00207
+is_a: MOD:00207 ! L-isoglutamyl-polyglutamic acid
 
 [Term]
 id: MOD:00875
@@ -17261,7 +17260,7 @@ property_value: MassMono "645.212965" xsd:float
 property_value: Origin "E" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:453
-is_a: MOD:00207
+is_a: MOD:00207 ! L-isoglutamyl-polyglutamic acid
 
 [Term]
 id: MOD:00876
@@ -17276,7 +17275,7 @@ property_value: DiffMono "161.068808" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:454
-is_a: MOD:00693
+is_a: MOD:00693 ! glycosylated residue
 
 [Term]
 id: MOD:00877
@@ -17290,7 +17289,7 @@ property_value: DiffMono "154.110613" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:455
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00878
@@ -17304,7 +17303,7 @@ property_value: DiffMono "122.084398" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:456
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00879
@@ -17318,7 +17317,7 @@ property_value: DiffMono "175.042199" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:457
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00880
@@ -17332,8 +17331,8 @@ property_value: DiffMono "220.991214" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:464
-relationship: derives_from MOD:00584
-is_a: MOD:01428
+relationship: derives_from MOD:00584 ! 4-sulfophenyl isothiocyanate derivatized residue
+is_a: MOD:01428 ! (13)C isotope tagged reagent
 
 [Term]
 id: MOD:00881
@@ -17365,7 +17364,7 @@ property_value: MassMono "146.051384" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:472
-is_a: MOD:00916
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:00883
@@ -17386,7 +17385,7 @@ property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: Unimod:2
-is_a: MOD:00674
+is_a: MOD:00674 ! amidated residue
 
 [Term]
 id: MOD:00884
@@ -17405,14 +17404,14 @@ property_value: MassAvg "146.21" xsd:float
 property_value: MassMono "146.051384" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
-is_a: MOD:00905
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00885
 name: ester crosslinked residues
 def: "A protein modification that crosslinks two residues by formation of an ester bond." [PubMed:18688235]
-is_a: MOD:00033
+is_a: MOD:00033 ! crosslinked residues
 
 [Term]
 id: MOD:00886
@@ -17433,14 +17432,14 @@ property_value: Origin "W" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:936
 xref: uniprot.ptm:PTM-0052
-is_a: MOD:01913
+is_a: MOD:01913 ! monochlorinated L-tryptophan
 
 [Term]
 id: MOD:00887
 name: methylated aspartic acid
 def: "A protein modification that effectively converts an L-aspartic acid residue to a methylated aspartic acid, such as aspartic acid 4-methyl ester." [PubMed:18688235]
-is_a: MOD:00427
-is_a: MOD:00904
+is_a: MOD:00427 ! methylated residue
+is_a: MOD:00904 ! modified L-aspartic acid residue
 
 [Term]
 id: MOD:00888
@@ -17457,8 +17456,8 @@ property_value: MassMono "99.067865" xsd:float
 property_value: Origin "P" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00915
-is_a: MOD:01700
+is_a: MOD:00915 ! modified L-proline residue
+is_a: MOD:01700 ! alpha-amino protonated residue
 
 [Term]
 id: MOD:00889
@@ -17476,11 +17475,11 @@ property_value: Origin "MOD:00888" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:36
-relationship: derives_from MOD:00075
-relationship: derives_from MOD:00888
-is_a: MOD:00712
-is_a: MOD:00710
-is_a: MOD:01686
+relationship: derives_from MOD:00075 ! N,N-dimethyl-L-proline
+relationship: derives_from MOD:00888 ! protonated L-proline (L-prolinium) residue
+is_a: MOD:00712 ! methylated proline
+is_a: MOD:00710 ! protonated-dimethylated residue
+is_a: MOD:01686 ! alpha-amino dimethylated residue
 
 [Term]
 id: MOD:00890
@@ -17501,8 +17500,8 @@ property_value: Origin "H" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:21
 xref: uniprot.ptm:PTM-0252
-is_a: MOD:00909
-is_a: MOD:01456
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:01456 ! N-phosphorylated residue
 
 [Term]
 id: MOD:00891
@@ -17516,8 +17515,8 @@ property_value: MassAvg "87.08" xsd:float
 property_value: MassMono "87.032028" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00664
-is_a: MOD:00859
+is_a: MOD:00664 ! stereoisomerized residue
+is_a: MOD:00859 ! modified residue that can arise from different natural residues
 
 [Term]
 id: MOD:00892
@@ -17535,23 +17534,23 @@ property_value: MassMono "87.032028" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0309
-is_a: MOD:00891
-is_a: MOD:00905
+is_a: MOD:00891 ! D-serine
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00893
 name: residues isobaric at 128.0-128.1
 def: "Natural or modified residues with a mass of 128.0-128.1 Da." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00616
+is_a: MOD:00616 ! residues isobaric at a resolution below 0.1 Da
 
 [Term]
 id: MOD:00894
 name: residues isobaric at 128.058578 Da
 def: "Natural or modified resiues with a mass of 128.058578 Da." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00569
-is_a: MOD:00893
+is_a: MOD:00569 ! residues isobaric at a resolution below 0.000001 Da
+is_a: MOD:00893 ! residues isobaric at 128.0-128.1
 
 [Term]
 id: MOD:00895
@@ -17564,8 +17563,8 @@ property_value: DiffFormula "C 27 H 31 N 9 O 15 P 2" xsd:string
 property_value: DiffMono "783.141485" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00697
-is_a: MOD:00861
+is_a: MOD:00697 ! flavin modified residue
+is_a: MOD:00861 ! phosphorus containing modified residue
 
 [Term]
 id: MOD:00896
@@ -17575,8 +17574,8 @@ subset: PSI-MOD-slim
 synonym: "FMNRes" EXACT PSI-MOD-label []
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00697
-is_a: MOD:00861
+is_a: MOD:00697 ! flavin modified residue
+is_a: MOD:00861 ! phosphorus containing modified residue
 
 [Term]
 id: MOD:00897
@@ -17591,9 +17590,9 @@ property_value: MassMono "779.682531" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00905
-relationship: has_functional_parent MOD:00052
-relationship: has_functional_parent MOD:00228
+is_a: MOD:00905 ! modified L-cysteine residue
+relationship: has_functional_parent MOD:00052 ! N-acetyl-L-cysteine
+relationship: has_functional_parent MOD:00228 ! S-diphytanylglycerol diether-L-cysteine
 
 [Term]
 id: MOD:00898
@@ -17611,7 +17610,7 @@ property_value: MassMono "679.520945" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:377
-is_a: MOD:00116
+is_a: MOD:00116 ! S-diacylglycerol-L-cysteine
 
 [Term]
 id: MOD:00899
@@ -17620,9 +17619,9 @@ def: "A protein modification that effectively converts an L-cysteine residue to
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00905
-relationship: has_functional_parent MOD:00069
-relationship: has_functional_parent MOD:00116
+is_a: MOD:00905 ! modified L-cysteine residue
+relationship: has_functional_parent MOD:00069 ! N-palmitoyl-L-cysteine
+relationship: has_functional_parent MOD:00116 ! S-diacylglycerol-L-cysteine
 
 [Term]
 id: MOD:00900
@@ -17639,9 +17638,9 @@ property_value: MassMono "917.750611" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00899
-relationship: has_functional_parent MOD:00069
-relationship: has_functional_parent MOD:00898
+is_a: MOD:00899 ! N-palmitoyl-S-diacylglycerol-L-cysteine
+relationship: has_functional_parent MOD:00069 ! N-palmitoyl-L-cysteine
+relationship: has_functional_parent MOD:00898 ! S-(sn-1-2-oleoyl-3-palmitoyl-glycerol)cysteine
 
 [Term]
 id: MOD:00901
@@ -17650,7 +17649,7 @@ def: "A protein modification that modifies an L-alanine." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "ModAla" EXACT PSI-MOD-label []
 property_value: Origin "A" xsd:string
-is_a: MOD:01157
+is_a: MOD:01157 ! protein modification categorized by amino acid modified
 
 [Term]
 id: MOD:00902
@@ -17659,7 +17658,7 @@ def: "A protein modification that modifies an L-arginine residue." [PubMed:18688
 subset: PSI-MOD-slim
 synonym: "ModArg" EXACT PSI-MOD-label []
 property_value: Origin "R" xsd:string
-is_a: MOD:01157
+is_a: MOD:01157 ! protein modification categorized by amino acid modified
 
 [Term]
 id: MOD:00903
@@ -17668,7 +17667,7 @@ def: "A protein modification that modifies an L-asparagine residue." [PubMed:186
 subset: PSI-MOD-slim
 synonym: "ModAsn" EXACT PSI-MOD-label []
 property_value: Origin "N" xsd:string
-is_a: MOD:01157
+is_a: MOD:01157 ! protein modification categorized by amino acid modified
 
 [Term]
 id: MOD:00904
@@ -17677,7 +17676,7 @@ def: "A protein modification that modifies an L-aspartic acid residue." [PubMed:
 subset: PSI-MOD-slim
 synonym: "ModAsp" EXACT PSI-MOD-label []
 property_value: Origin "D" xsd:string
-is_a: MOD:01157
+is_a: MOD:01157 ! protein modification categorized by amino acid modified
 
 [Term]
 id: MOD:00905
@@ -17686,7 +17685,7 @@ def: "A protein modification that modifies an L-cysteine residue." [PubMed:18688
 subset: PSI-MOD-slim
 synonym: "ModCys" EXACT PSI-MOD-label []
 property_value: Origin "C" xsd:string
-is_a: MOD:01157
+is_a: MOD:01157 ! protein modification categorized by amino acid modified
 
 [Term]
 id: MOD:00906
@@ -17695,7 +17694,7 @@ def: "A protein modification that modifies an L-glutamic acid residue." [PubMed:
 subset: PSI-MOD-slim
 synonym: "ModGlu" EXACT PSI-MOD-label []
 property_value: Origin "E" xsd:string
-is_a: MOD:01157
+is_a: MOD:01157 ! protein modification categorized by amino acid modified
 
 [Term]
 id: MOD:00907
@@ -17704,7 +17703,7 @@ def: "A protein modification that modifies an L-glutamine residue." [PubMed:1868
 subset: PSI-MOD-slim
 synonym: "ModGln" EXACT PSI-MOD-label []
 property_value: Origin "Q" xsd:string
-is_a: MOD:01157
+is_a: MOD:01157 ! protein modification categorized by amino acid modified
 
 [Term]
 id: MOD:00908
@@ -17713,7 +17712,7 @@ def: "A protein modification that modifies a glycine residue." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "ModGly" EXACT PSI-MOD-label []
 property_value: Origin "G" xsd:string
-is_a: MOD:01157
+is_a: MOD:01157 ! protein modification categorized by amino acid modified
 
 [Term]
 id: MOD:00909
@@ -17722,7 +17721,7 @@ def: "A protein modification that modifies an L-histidine residue." [PubMed:1868
 subset: PSI-MOD-slim
 synonym: "ModHis" EXACT PSI-MOD-label []
 property_value: Origin "H" xsd:string
-is_a: MOD:01157
+is_a: MOD:01157 ! protein modification categorized by amino acid modified
 
 [Term]
 id: MOD:00910
@@ -17731,7 +17730,7 @@ def: "A protein modification that modifies an L-isoleucine residue." [PubMed:186
 subset: PSI-MOD-slim
 synonym: "ModIle" EXACT PSI-MOD-label []
 property_value: Origin "I" xsd:string
-is_a: MOD:01157
+is_a: MOD:01157 ! protein modification categorized by amino acid modified
 
 [Term]
 id: MOD:00911
@@ -17740,7 +17739,7 @@ def: "A protein modification that modifies an L-leucine residue." [PubMed:186882
 subset: PSI-MOD-slim
 synonym: "ModLeu" EXACT PSI-MOD-label []
 property_value: Origin "L" xsd:string
-is_a: MOD:01157
+is_a: MOD:01157 ! protein modification categorized by amino acid modified
 
 [Term]
 id: MOD:00912
@@ -17749,7 +17748,7 @@ def: "A protein modification that modifies an L-lysine residue." [PubMed:1868823
 subset: PSI-MOD-slim
 synonym: "ModLys" EXACT PSI-MOD-label []
 property_value: Origin "K" xsd:string
-is_a: MOD:01157
+is_a: MOD:01157 ! protein modification categorized by amino acid modified
 
 [Term]
 id: MOD:00913
@@ -17758,7 +17757,7 @@ def: "A protein modification that modifies an L-methionine residue." [PubMed:186
 subset: PSI-MOD-slim
 synonym: "ModMet" EXACT PSI-MOD-label []
 property_value: Origin "M" xsd:string
-is_a: MOD:01157
+is_a: MOD:01157 ! protein modification categorized by amino acid modified
 
 [Term]
 id: MOD:00914
@@ -17767,7 +17766,7 @@ def: "A protein modification that modifies an L-phenylalanine residue." [PubMed:
 subset: PSI-MOD-slim
 synonym: "ModPhe" EXACT PSI-MOD-label []
 property_value: Origin "F" xsd:string
-is_a: MOD:01157
+is_a: MOD:01157 ! protein modification categorized by amino acid modified
 
 [Term]
 id: MOD:00915
@@ -17776,7 +17775,7 @@ def: "A protein modification that modifies an L-proline residue." [PubMed:186882
 subset: PSI-MOD-slim
 synonym: "ModPro" EXACT PSI-MOD-label []
 property_value: Origin "P" xsd:string
-is_a: MOD:01157
+is_a: MOD:01157 ! protein modification categorized by amino acid modified
 
 [Term]
 id: MOD:00916
@@ -17785,7 +17784,7 @@ def: "A protein modification that modifies an L-serine residue." [PubMed:1868823
 subset: PSI-MOD-slim
 synonym: "ModSer" EXACT PSI-MOD-label []
 property_value: Origin "S" xsd:string
-is_a: MOD:01157
+is_a: MOD:01157 ! protein modification categorized by amino acid modified
 
 [Term]
 id: MOD:00917
@@ -17794,7 +17793,7 @@ def: "A protein modification that modifies an L-threonine residue." [PubMed:1868
 subset: PSI-MOD-slim
 synonym: "ModThr" EXACT PSI-MOD-label []
 property_value: Origin "T" xsd:string
-is_a: MOD:01157
+is_a: MOD:01157 ! protein modification categorized by amino acid modified
 
 [Term]
 id: MOD:00918
@@ -17803,7 +17802,7 @@ def: "A protein modification that modifies an L-tryptophan residue." [PubMed:186
 subset: PSI-MOD-slim
 synonym: "ModTrp" EXACT PSI-MOD-label []
 property_value: Origin "W" xsd:string
-is_a: MOD:01157
+is_a: MOD:01157 ! protein modification categorized by amino acid modified
 
 [Term]
 id: MOD:00919
@@ -17812,7 +17811,7 @@ def: "A protein modification that modifies an L-tyrosine residue." [PubMed:18688
 subset: PSI-MOD-slim
 synonym: "ModTyr" EXACT PSI-MOD-label []
 property_value: Origin "Y" xsd:string
-is_a: MOD:01157
+is_a: MOD:01157 ! protein modification categorized by amino acid modified
 
 [Term]
 id: MOD:00920
@@ -17821,7 +17820,7 @@ def: "A protein modification that modifies an L-valine residue." [PubMed:1868823
 subset: PSI-MOD-slim
 synonym: "ModVal" EXACT PSI-MOD-label []
 property_value: Origin "V" xsd:string
-is_a: MOD:01157
+is_a: MOD:01157 ! protein modification categorized by amino acid modified
 
 [Term]
 id: MOD:00921
@@ -17844,8 +17843,8 @@ property_value: MassMono "775.307341" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:494
-is_a: MOD:00848
-is_a: MOD:00905
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00923
@@ -17862,8 +17861,8 @@ property_value: MassMono "787.307341" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:495
-is_a: MOD:00848
-is_a: MOD:00905
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00924
@@ -17883,11 +17882,11 @@ property_value: Origin "K, T" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0326
-is_a: MOD:00688
-is_a: MOD:02056
-is_a: MOD:02051
-is_a: MOD:00954
-is_a: MOD:01875
+is_a: MOD:00688 ! isopeptide crosslinked residues
+is_a: MOD:02056 ! crosslinked L-threonine residue
+is_a: MOD:02051 ! crosslinked L-lysine residue
+is_a: MOD:00954 ! crosslinked residues with loss of water
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:00925
@@ -17902,7 +17901,7 @@ property_value: DiffMono "192.063388" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:490
-is_a: MOD:00693
+is_a: MOD:00693 ! glycosylated residue
 
 [Term]
 id: MOD:00926
@@ -17930,8 +17929,8 @@ property_value: DiffMono "34.063117" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:510
-is_a: MOD:00839
-is_a: MOD:00842
+is_a: MOD:00839 ! (2)H deuterium labeled residue
+is_a: MOD:00842 ! (13)C labeled residue
 
 [Term]
 id: MOD:00928
@@ -17946,7 +17945,7 @@ property_value: DiffMono "227.224915" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:513
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00929
@@ -17966,8 +17965,8 @@ property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:512
 xref: uniprot.ptm:PTM-0511
-is_a: MOD:00767
-is_a: MOD:00912
+is_a: MOD:00767 ! glycated residue
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:00930
@@ -17982,8 +17981,8 @@ property_value: MassMono "395.127682" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:514
-is_a: MOD:00848
-is_a: MOD:00919
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00919 ! modified L-tyrosine residue
 
 [Term]
 id: MOD:00931
@@ -17997,7 +17996,7 @@ property_value: DiffMono "234.161980" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:498
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00932
@@ -18014,8 +18013,8 @@ property_value: MassMono "401.031934" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:499
-is_a: MOD:00905
-is_a: MOD:01428
+is_a: MOD:00905 ! modified L-cysteine residue
+is_a: MOD:01428 ! (13)C isotope tagged reagent
 
 [Term]
 id: MOD:00933
@@ -18033,8 +18032,8 @@ property_value: MassMono "210.111676" xsd:float
 property_value: Origin "R" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:319
-is_a: MOD:00630
-is_a: MOD:00902
+is_a: MOD:00630 ! C3-H2-O adduct (+54 amu) of malondialdehyde with lysine or methylglyoxal with arginine.
+is_a: MOD:00902 ! modified L-arginine residue
 
 [Term]
 id: MOD:00934
@@ -18051,8 +18050,8 @@ property_value: MassMono "462.272987" xsd:float
 property_value: Origin "R" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:506
-is_a: MOD:00846
-is_a: MOD:00902
+is_a: MOD:00846 ! levuglandinyl (prostaglandin H2) adduct
+is_a: MOD:00902 ! modified L-arginine residue
 
 [Term]
 id: MOD:00935
@@ -18067,8 +18066,8 @@ property_value: MassAvg "83.09" xsd:float
 property_value: MassMono "83.037114" xsd:float
 property_value: Origin "M" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00431
-is_a: MOD:00913
+is_a: MOD:00431 ! modified residue with a secondary neutral loss
+is_a: MOD:00913 ! modified L-methionine residue
 
 [Term]
 id: MOD:00936
@@ -18082,7 +18081,7 @@ property_value: DiffMono "348.193674" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:504
-is_a: MOD:00846
+is_a: MOD:00846 ! levuglandinyl (prostaglandin H2) adduct
 
 [Term]
 id: MOD:00937
@@ -18099,8 +18098,8 @@ property_value: MassMono "446.278072" xsd:float
 property_value: Origin "R" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:505
-is_a: MOD:00846
-is_a: MOD:00902
+is_a: MOD:00846 ! levuglandinyl (prostaglandin H2) adduct
+is_a: MOD:00902 ! modified L-arginine residue
 
 [Term]
 id: MOD:00938
@@ -18114,7 +18113,7 @@ property_value: DiffMono "332.198759" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:503
-is_a: MOD:00846
+is_a: MOD:00846 ! levuglandinyl (prostaglandin H2) adduct
 
 [Term]
 id: MOD:00939
@@ -18131,8 +18130,8 @@ property_value: MassMono "232.051778" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:500
-is_a: MOD:00848
-is_a: MOD:00905
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00940
@@ -18147,7 +18146,7 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:501
-is_a: MOD:00840
+is_a: MOD:00840 ! isocyanate reagent derivatized residue
 
 [Term]
 id: MOD:00941
@@ -18164,8 +18163,8 @@ property_value: MassMono "205.079944" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:488
-is_a: MOD:00848
-is_a: MOD:00905
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00942
@@ -18185,8 +18184,8 @@ property_value: MassMono "132.120070" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:481
-is_a: MOD:00837
-is_a: MOD:00912
+is_a: MOD:00837 ! deuterium tetrasubstituted residue
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:00943
@@ -18200,7 +18199,7 @@ property_value: DiffMono "128.107539" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:476
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00944
@@ -18214,8 +18213,8 @@ property_value: DiffMono "137.164030" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:477
-relationship: derives_from MOD:00943
-is_a: MOD:01431
+relationship: derives_from MOD:00943 ! 4-trimethylammoniumbutanoyl derivatized residue
+is_a: MOD:01431 ! (2)H deuterium tagged reagent
 
 [Term]
 id: MOD:00945
@@ -18234,13 +18233,13 @@ id: MOD:00946
 name: crosslinked residues with loss of ammonia
 def: "A protein modification that crosslinks two residues with a covalent bond and the loss of ammonia." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00033
+is_a: MOD:00033 ! crosslinked residues
 
 [Term]
 id: MOD:00947
 name: DeltaMass
 def: "Entries from DeltaMass see http://www.abrf.org/index.cfm/dm.home?AvgMass=all." [PubMed:18688235]
-is_a: MOD:00032
+is_a: MOD:00032 ! uncategorized protein modification
 
 [Term]
 id: MOD:00948
@@ -18281,9 +18280,9 @@ property_value: MassAvg "129.12" xsd:float
 property_value: MassMono "129.042593" xsd:float
 property_value: Origin "E" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00906
-is_a: MOD:00957
-is_a: MOD:00960
+is_a: MOD:00906 ! modified L-glutamic acid residue
+is_a: MOD:00957 ! modified residue with neutral loss of carbon dioxide
+is_a: MOD:00960 ! decarboxylated residue
 
 [Term]
 id: MOD:00952
@@ -18307,9 +18306,9 @@ property_value: MassMono "154.037842" xsd:float
 property_value: Origin "D, G" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: uniprot.ptm:PTM-0312
-is_a: MOD:02043
-is_a: MOD:00954
-is_a: MOD:01628
+is_a: MOD:02043 ! crosslinked L-aspartic acid residue
+is_a: MOD:00954 ! crosslinked residues with loss of water
+is_a: MOD:01628 ! (2-aminosuccinimidyl)acetic acid
 
 [Term]
 id: MOD:00953
@@ -18330,16 +18329,16 @@ property_value: MassAvg "198.18" xsd:float
 property_value: MassMono "198.064057" xsd:float
 property_value: Origin "E, S" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02045
-is_a: MOD:00954
-is_a: MOD:01977
+is_a: MOD:02045 ! crosslinked L-glutamic acid residue
+is_a: MOD:00954 ! crosslinked residues with loss of water
+is_a: MOD:01977 ! O-(L-isoglutamyl)-L-serine
 
 [Term]
 id: MOD:00954
 name: crosslinked residues with loss of water
 def: "A protein modification that crosslinks two residues with a covalent bond and the loss of water." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00033
+is_a: MOD:00033 ! crosslinked residues
 
 [Term]
 id: MOD:00955
@@ -18355,9 +18354,9 @@ property_value: MassAvg "206.20" xsd:float
 property_value: MassMono "206.080376" xsd:float
 property_value: Origin "H, S" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02048
-is_a: MOD:02055
-is_a: MOD:00954
+is_a: MOD:02048 ! crosslinked L-histidine residue
+is_a: MOD:02055 ! crosslinked L-serine residue
+is_a: MOD:00954 ! crosslinked residues with loss of water
 
 [Term]
 id: MOD:00956
@@ -18371,7 +18370,7 @@ property_value: Formula "C 6 H 11 N 1 O 1" xsd:string
 property_value: MassAvg "113.16" xsd:float
 property_value: MassMono "113.084064" xsd:float
 property_value: Origin "M" xsd:string
-is_a: MOD:01026
+is_a: MOD:01026 ! norleucine residue (Nle)
 
 [Term]
 id: MOD:00957
@@ -18383,7 +18382,7 @@ property_value: DiffFormula "C -1 H 0 N 0 O -2" xsd:string
 property_value: DiffMono "-43.989829" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00431
+is_a: MOD:00431 ! modified residue with a secondary neutral loss
 
 [Term]
 id: MOD:00958
@@ -18391,7 +18390,7 @@ name: crosslink between Arg and His sidechains
 def: "modification from DeltaMass" [DeltaMass:0]
 comment: Cross-link 2; From DeltaMass: Average Mass: -5
 property_value: Origin "H, R" xsd:string
-is_a: MOD:00692
+is_a: MOD:00692 ! uncategorized crosslinked residues
 
 [Term]
 id: MOD:00959
@@ -18399,7 +18398,7 @@ name: 3,3',5,5'-TerTyr (Crosslink)
 def: "modification from DeltaMass" [DeltaMass:0]
 comment: Cross-link 4; From DeltaMass: Average Mass: -4
 property_value: Origin "Y, Y, Y, Y" xsd:string
-is_a: MOD:00692
+is_a: MOD:00692 ! uncategorized crosslinked residues
 
 [Term]
 id: MOD:00960
@@ -18410,7 +18409,7 @@ property_value: DiffFormula "C -1 H 0 N 0 O -2" xsd:string
 property_value: DiffMono "-43.989829" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:00961
@@ -18425,9 +18424,9 @@ property_value: Formula "C 6 H 10 N 2 O 2 S 2" xsd:string
 property_value: MassAvg "206.28" xsd:float
 property_value: MassMono "206.018370" xsd:float
 property_value: Origin "MOD:00034" xsd:string
-is_a: MOD:00905
-is_a: MOD:01473
-relationship: derives_from MOD:00034
+is_a: MOD:00905 ! modified L-cysteine residue
+is_a: MOD:01473 ! hydrogenated residue
+relationship: derives_from MOD:00034 ! L-cystine (cross-link)
 
 [Term]
 id: MOD:00962
@@ -18442,8 +18441,8 @@ property_value: MassAvg "188.23" xsd:float
 property_value: MassMono "188.094963" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00918
-is_a: MOD:01473
+is_a: MOD:00918 ! modified L-tryptophan residue
+is_a: MOD:01473 ! hydrogenated residue
 
 [Term]
 id: MOD:00963
@@ -18469,7 +18468,7 @@ property_value: MassAvg "140.19" xsd:float
 property_value: MassMono "140.094963" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:00965
@@ -18486,7 +18485,7 @@ property_value: MassMono "116.017010" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00905
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:00966
@@ -18501,7 +18500,7 @@ property_value: MassAvg "198.22" xsd:float
 property_value: MassMono "198.079313" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00918
+is_a: MOD:00918 ! modified L-tryptophan residue
 
 [Term]
 id: MOD:00967
@@ -18516,7 +18515,7 @@ property_value: Formula "C 12 H 21 N 2 O 5" xsd:string
 property_value: MassAvg "273.31" xsd:float
 property_value: MassMono "273.145047" xsd:float
 property_value: Origin "K, K" xsd:string
-is_a: MOD:02051
+is_a: MOD:02051 ! crosslinked L-lysine residue
 
 [Term]
 id: MOD:00968
@@ -18543,7 +18542,7 @@ def: "modification from DeltaMass" [DeltaMass:37]
 comment: From DeltaMass: Average Mass: 15 Average Mass Change:15 Notes:In going from Lys to hydroxy-allysine, two separate reactions are involved:1. the oxidative deamination converting Lys to allysine (-CH2NH2 being converted to -CHO) with a net mass change of -1;2.conversion of allysine to delta-hydroxy-allysine (-CH2-CHO being converted to -CH(OH)-CHO) with a mass change of +16. The net change from Lys to hydroxyallysine thus is +15.
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:00971
@@ -18558,8 +18557,8 @@ property_value: MassAvg "153.14" xsd:float
 property_value: MassMono "153.053826" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00909
-is_a: MOD:00677
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:00677 ! hydroxylated residue
 
 [Term]
 id: MOD:00972
@@ -18578,8 +18577,8 @@ property_value: MassMono "224.978926" xsd:float
 property_value: Origin "F" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:340
-is_a: MOD:02086
-is_a: MOD:01912
+is_a: MOD:02086 ! brominated phenylalanine
+is_a: MOD:01912 ! monobrominated residue
 
 [Term]
 id: MOD:00973
@@ -18588,7 +18587,7 @@ def: "modification from DeltaMass" [DeltaMass:355]
 comment: From DeltaMass: Average Mass: 32 Monoisotopic Mass Change:31.99 Average Mass Change:32 References:Amici A, Levine, RL, Tsai, L, and Stadtman, ER: Conversion of amino acid residues in proteins and amino acid homopolymers to carbonyl derivatives by metal-catalyzed oxidation reactions. Journal of Biological Chemistry 264: 3341-3346 1989.Rod Levine (unpublished)
 property_value: Origin "P" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:00974
@@ -18603,8 +18602,8 @@ property_value: MassAvg "197.02" xsd:float
 property_value: MassMono "197.024356" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
-relationship: derives_from MOD:01046
-is_a: MOD:00987
+relationship: derives_from MOD:01046 ! 3'-chloro-L-tyrosine
+is_a: MOD:00987 ! chlorinated tyrosine
 
 [Term]
 id: MOD:00975
@@ -18619,8 +18618,8 @@ property_value: MassAvg "199.02" xsd:float
 property_value: MassMono "199.021406" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
-relationship: derives_from MOD:01046
-is_a: MOD:00987
+relationship: derives_from MOD:01046 ! 3'-chloro-L-tyrosine
+is_a: MOD:00987 ! chlorinated tyrosine
 
 [Term]
 id: MOD:00976
@@ -18644,7 +18643,7 @@ property_value: DiffAvg "43.96" xsd:float
 property_value: DiffFormula "H -2 Na 2" xsd:string
 property_value: DiffMono "43.963888" xsd:float
 property_value: Origin "X" xsd:string
-is_a: MOD:00747
+is_a: MOD:00747 ! sodium containing modified residue
 
 [Term]
 id: MOD:00978
@@ -18653,7 +18652,7 @@ def: "modification from DeltaMass" [DeltaMass:345]
 comment: From DeltaMass: Average Mass: 51 Average Mass Change: 51 References:Lukszo, Patterson, Albericio, and Kates, Letters in Peptide Science 3, 157-166(1996) Notes:The side reaction can be very significant, and the level to which it occurs depends on how the C-terminal Cys is anchored and what the side-chain protecting group is. The mechanism involves piperidine-mediated beta-elimination of sulfur (with the protecting group on), followed by addition of piperidine across the C-terminaldehydroalanine. Since this last-mentioned step creates a chiral center, a mixture of diastereomers is formed which in special cases can be separatedby HPLC. Another problem with C-terminal Cys is racemization; some references in the review article by Andreu, Albericio, Sole, Munson, Ferrer, and Barany in Pennington-Dunn Peptide Synthesis and Purification Protocols, vol 35, 1994, pp. 91-169.
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:00979
@@ -18662,7 +18661,7 @@ def: "modification from DeltaMass" [DeltaMass:0]
 comment: From DeltaMass: Average Mass: 56
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:00980
@@ -18684,8 +18683,8 @@ property_value: DiffAvg "60.07" xsd:float
 property_value: DiffFormula "H -2 K 1 Na 1" xsd:string
 property_value: DiffMono "59.937826" xsd:float
 property_value: Origin "X" xsd:string
-is_a: MOD:00747
-is_a: MOD:00849
+is_a: MOD:00747 ! sodium containing modified residue
+is_a: MOD:00849 ! potassium containing modified residue
 
 [Term]
 id: MOD:00982
@@ -18702,8 +18701,8 @@ property_value: MassAvg "150.05" xsd:float
 property_value: MassMono "150.953635" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00916
-is_a: MOD:02088
+is_a: MOD:00916 ! modified L-serine residue
+is_a: MOD:02088 ! natural, standard, encoded residue substitution
 
 [Term]
 id: MOD:00983
@@ -18712,7 +18711,7 @@ def: "modification from DeltaMass" [DeltaMass:67]
 comment: From DeltaMass: Average Mass: 67 Average Mass Change:67 References:http://www.abrf.org/archives/hmail/0008/0007.html Notes:1.) Get rid of the DBU. It can cause piperidine amides at Asp residues. The tbu ester side chain comes off during synthesis and the residue is trans-amidated with piperidine (+67Da by MS). If you haven't yet seen this, you will. Even \"normal\" 20% pip/DMF (NMP) will cause this, but less frequently. Literature exists for this; I don't remember the exact reference. David H. Singleton Scientist Pfizer Central Research PO Box 8118-101 Eastern Point Road Groton, CT 06340 (860)441-4404.
 property_value: Origin "D" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:00984
@@ -18727,8 +18726,8 @@ property_value: MassAvg "230.99" xsd:float
 property_value: MassMono "230.985384" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
-relationship: derives_from MOD:01045
-is_a: MOD:00987
+relationship: derives_from MOD:01045 ! 3',5'-dichloro-L-tyrosine
+is_a: MOD:00987 ! chlorinated tyrosine
 
 [Term]
 id: MOD:00985
@@ -18737,8 +18736,8 @@ def: "A protein modification that effectively substitutes a hydrogen atom of an
 subset: PSI-MOD-slim
 synonym: "HalTyr" EXACT PSI-MOD-label []
 property_value: Origin "Y" xsd:string
-is_a: MOD:00694
-is_a: MOD:00919
+is_a: MOD:00694 ! halogen containing residue
+is_a: MOD:00919 ! modified L-tyrosine residue
 
 [Term]
 id: MOD:00986
@@ -18753,8 +18752,8 @@ property_value: MassAvg "232.98" xsd:float
 property_value: MassMono "232.982434" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
-relationship: derives_from MOD:01045
-is_a: MOD:00987
+relationship: derives_from MOD:01045 ! 3',5'-dichloro-L-tyrosine
+is_a: MOD:00987 ! chlorinated tyrosine
 
 [Term]
 id: MOD:00987
@@ -18762,8 +18761,8 @@ name: chlorinated tyrosine
 def: "A protein modification that effectively substitutes a hydrogen atom of an L-tyrosine residue with a chlorine atom." [PubMed:18688235]
 synonym: "ClTyr" EXACT PSI-MOD-label []
 property_value: Origin "Y" xsd:string
-is_a: MOD:00753
-is_a: MOD:00985
+is_a: MOD:00753 ! chlorinated residue
+is_a: MOD:00985 ! halogenated tyrosine
 
 [Term]
 id: MOD:00988
@@ -18771,8 +18770,8 @@ name: brominated tyrosine
 def: "A protein modification that effectively substitutes a hydrogen atom of an L-tyrosine residue with a bromine atom." [PubMed:18688235]
 synonym: "BrTyr" EXACT PSI-MOD-label []
 property_value: Origin "Y" xsd:string
-is_a: MOD:00754
-is_a: MOD:00985
+is_a: MOD:00754 ! brominated residue
+is_a: MOD:00985 ! halogenated tyrosine
 
 [Term]
 id: MOD:00989
@@ -18797,8 +18796,8 @@ property_value: MassAvg "234.98" xsd:float
 property_value: MassMono "234.979484" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
-relationship: derives_from MOD:01045
-is_a: MOD:00987
+relationship: derives_from MOD:01045 ! 3',5'-dichloro-L-tyrosine
+is_a: MOD:00987 ! chlorinated tyrosine
 
 [Term]
 id: MOD:00991
@@ -18813,7 +18812,7 @@ property_value: MassAvg "177.22" xsd:float
 property_value: MassMono "177.045964" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:00992
@@ -18828,7 +18827,7 @@ property_value: MassAvg "203.19" xsd:float
 property_value: MassMono "203.079373" xsd:float
 property_value: Origin "E" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00906
+is_a: MOD:00906 ! modified L-glutamic acid residue
 
 [Term]
 id: MOD:00993
@@ -18841,7 +18840,7 @@ property_value: DiffFormula "C 6 H 4" xsd:string
 property_value: DiffMono "76.031300" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00994
@@ -18856,8 +18855,8 @@ property_value: MassAvg "240.97" xsd:float
 property_value: MassMono "240.973841" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
-relationship: derives_from MOD:01025
-is_a: MOD:01000
+relationship: derives_from MOD:01025 ! 3'-bromo-L-tyrosine
+is_a: MOD:01000 ! monobrominated tyrosine
 
 [Term]
 id: MOD:00995
@@ -18872,8 +18871,8 @@ property_value: MassAvg "226.98" xsd:float
 property_value: MassMono "226.976879" xsd:float
 property_value: Origin "F" xsd:string
 property_value: Source "artifact" xsd:string
-relationship: derives_from MOD:00183
-is_a: MOD:02086
+relationship: derives_from MOD:00183 ! L-2'-bromophenylalanine
+is_a: MOD:02086 ! brominated phenylalanine
 
 [Term]
 id: MOD:00996
@@ -18888,8 +18887,8 @@ property_value: MassAvg "242.97" xsd:float
 property_value: MassMono "242.971794" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
-relationship: derives_from MOD:01025
-is_a: MOD:01000
+relationship: derives_from MOD:01025 ! 3'-bromo-L-tyrosine
+is_a: MOD:01000 ! monobrominated tyrosine
 
 [Term]
 id: MOD:00997
@@ -18902,7 +18901,7 @@ property_value: DiffFormula "C 6 H 10" xsd:string
 property_value: DiffMono "82.078250" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:00998
@@ -18911,8 +18910,8 @@ def: "A protein modification that effectively substitutes a hydrogen atom of an
 subset: PSI-MOD-slim
 synonym: "ITyr" EXACT PSI-MOD-label []
 property_value: Origin "Y" xsd:string
-is_a: MOD:00755
-is_a: MOD:00985
+is_a: MOD:00755 ! iodinated residue
+is_a: MOD:00985 ! halogenated tyrosine
 
 [Term]
 id: MOD:00999
@@ -18930,7 +18929,7 @@ name: monobrominated tyrosine
 def: "A protein modification that effectively substitutes one hydrogen atom of an L-tyrosine residue with one bromine atom." [PubMed:18688235]
 synonym: "Br1Tyr" EXACT PSI-MOD-label []
 property_value: Origin "Y" xsd:string
-is_a: MOD:00988
+is_a: MOD:00988 ! brominated tyrosine
 
 [Term]
 id: MOD:01001
@@ -18949,7 +18948,7 @@ property_value: MassAvg "85.11" xsd:float
 property_value: MassMono "85.052764" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00850
+is_a: MOD:00850 ! unnatural residue
 
 [Term]
 id: MOD:01002
@@ -18961,7 +18960,7 @@ property_value: DiffFormula "C 4 H 7 N 1 O 1" xsd:string
 property_value: DiffMono "85.052764" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01003
@@ -18970,7 +18969,7 @@ def: "modification from DeltaMass" [DeltaMass:0]
 comment: From DeltaMass: Average Mass: 86
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01004
@@ -18982,7 +18981,7 @@ property_value: DiffFormula "C 3 H 6 N 2 O 1" xsd:string
 property_value: DiffMono "86.048013" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01005
@@ -18992,7 +18991,7 @@ comment: From DeltaMass: Average Mass: 88
 synonym: "StBu" EXACT DeltaMass-label []
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01006
@@ -19003,7 +19002,7 @@ synonym: "Dibromo" RELATED PSI-MS-label []
 synonym: "Dibromo" RELATED Unimod-description []
 property_value: Origin "Y" xsd:string
 xref: Unimod:534
-is_a: MOD:00988
+is_a: MOD:00988 ! brominated tyrosine
 
 [Term]
 id: MOD:01007
@@ -19015,7 +19014,7 @@ property_value: DiffFormula "C 7 H 6" xsd:string
 property_value: DiffMono "90.046950" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01008
@@ -19027,7 +19026,7 @@ property_value: DiffFormula "C 7 H 6" xsd:string
 property_value: DiffMono "90.046950" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01009
@@ -19041,8 +19040,8 @@ property_value: Formula "C 5 H 5 N 1 O 1" xsd:string
 property_value: MassAvg "95.10" xsd:float
 property_value: MassMono "95.037114" xsd:float
 property_value: Origin "P" xsd:string
-is_a: MOD:00915
-is_a: MOD:01888
+is_a: MOD:00915 ! modified L-proline residue
+is_a: MOD:01888 ! didehydrogenated residue
 
 [Term]
 id: MOD:01010
@@ -19054,9 +19053,9 @@ property_value: DiffFormula "C 2 F 3 H -1 O 1" xsd:string
 property_value: DiffMono "95.982299" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00498
-is_a: MOD:00649
-is_a: MOD:00848
+is_a: MOD:00498 ! fluorinated residue
+is_a: MOD:00649 ! acylated residue
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01011
@@ -19065,7 +19064,7 @@ def: "modification from DeltaMass" [DeltaMass:0]
 comment: From DeltaMass: Average Mass: 97
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01012
@@ -19080,8 +19079,8 @@ property_value: MassAvg "302.27" xsd:float
 property_value: MassMono "301.987857" xsd:float
 property_value: Origin "MOD:00034" xsd:string
 property_value: Source "artifact" xsd:string
-relationship: derives_from MOD:00034
-is_a: MOD:00675
+relationship: derives_from MOD:00034 ! L-cystine (cross-link)
+is_a: MOD:00675 ! oxidized residue
 
 [Term]
 id: MOD:01013
@@ -19089,7 +19088,7 @@ name: tetramethylguanidinium termination by-product on amine
 def: "modification from DeltaMass" [DeltaMass:0]
 comment: From DeltaMass: Average Mass: 98
 property_value: Origin "X" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01014
@@ -19097,7 +19096,7 @@ name: phosphate/sulphate adduct of proteins
 def: "modification from DeltaMass" [DeltaMass:358]
 comment: From DeltaMass: Average Mass: 98 Formula:H3PO4 or H2SO4 Monoisotopic Mass Change:97.97 Average Mass Change:98 Notes:Proteins may pick up non-covalent salt adducts during purification. Phosphate and sulphate salts are commonly used and may be observed as +98 amu adducts (or multiples thereof) forming ion pairs with basic residues. Monoisotopic masses H2SO4 97.967, H3PO4 97.977
 property_value: Origin "X" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01015
@@ -19111,7 +19110,7 @@ property_value: MassAvg "99.13" xsd:float
 property_value: MassMono "99.068414" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00850
+is_a: MOD:00850 ! unnatural residue
 
 [Term]
 id: MOD:01016
@@ -19121,7 +19120,7 @@ comment: From DeltaMass: Average Mass: 100
 synonym: "tBoc" EXACT DeltaMass-label []
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01017
@@ -19141,7 +19140,7 @@ comment: From DeltaMass: Average Mass: 104
 synonym: "Meb" EXACT DeltaMass-label []
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01019
@@ -19151,7 +19150,7 @@ comment: From DeltaMass: Average Mass: 106
 synonym: "HMP" EXACT DeltaMass-label []
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01020
@@ -19160,7 +19159,7 @@ def: "modification from DeltaMass" [DeltaMass:0]
 comment: From DeltaMass: Average Mass: 106
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01021
@@ -19169,7 +19168,7 @@ def: "modification from DeltaMass" [DeltaMass:0]
 comment: From DeltaMass: Average Mass: 106
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01022
@@ -19184,9 +19183,9 @@ property_value: MassAvg "111.14" xsd:float
 property_value: MassMono "111.068414" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00601
-is_a: MOD:00912
-is_a: MOD:01160
+is_a: MOD:00601 ! cyclized residue
+is_a: MOD:00912 ! modified L-lysine residue
+is_a: MOD:01160 ! deaminated residue
 
 [Term]
 id: MOD:01023
@@ -19200,7 +19199,7 @@ property_value: Formula "Br 2 C 9 H 7 N 1 O 2" xsd:string
 property_value: MassAvg "320.97" xsd:float
 property_value: MassMono "318.884353" xsd:float
 property_value: Origin "Y" xsd:string
-is_a: MOD:01006
+is_a: MOD:01006 ! dibrominated tyrosine
 
 [Term]
 id: MOD:01024
@@ -19223,9 +19222,9 @@ property_value: Origin "P" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:35
 xref: uniprot.ptm:PTM-0149
-is_a: MOD:00425
-is_a: MOD:00594
-is_a: MOD:00678
+is_a: MOD:00425 ! monohydroxylated residue
+is_a: MOD:00594 ! residues isobaric at 113.047678 Da
+is_a: MOD:00678 ! hydroxylated proline
 
 [Term]
 id: MOD:01025
@@ -19239,7 +19238,7 @@ property_value: Formula "Br 1 C 9 H 8 N 1 O 2" xsd:string
 property_value: MassAvg "242.07" xsd:float
 property_value: MassMono "240.973841" xsd:float
 property_value: Origin "Y" xsd:string
-is_a: MOD:01000
+is_a: MOD:01000 ! monobrominated tyrosine
 
 [Term]
 id: MOD:01026
@@ -19251,8 +19250,8 @@ property_value: MassAvg "113.16" xsd:float
 property_value: MassMono "113.084064" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00850
-is_a: MOD:00306
+is_a: MOD:00850 ! unnatural residue
+is_a: MOD:00306 ! residues isobaric at 113.084064 Da
 
 [Term]
 id: MOD:01027
@@ -19262,7 +19261,7 @@ comment: From DeltaMass: Average Mass: 114
 synonym: "Aoc" EXACT DeltaMass-label []
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01028
@@ -19277,8 +19276,8 @@ property_value: MassAvg "197.62" xsd:float
 property_value: MassMono "197.024356" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00987
-is_a: MOD:01911
+is_a: MOD:00987 ! chlorinated tyrosine
+is_a: MOD:01911 ! monochlorinated residue
 
 [Term]
 id: MOD:01029
@@ -19292,7 +19291,7 @@ property_value: DiffFormula "C 4 H 4 O 3" xsd:string
 property_value: DiffMono "100.016044" xsd:float
 property_value: Origin "X" xsd:string
 xref: Unimod:64
-is_a: MOD:00649
+is_a: MOD:00649 ! acylated residue
 
 [Term]
 id: MOD:01030
@@ -19302,7 +19301,7 @@ comment: From DeltaMass: Average Mass: 117
 synonym: "HOBt" EXACT DeltaMass-label []
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01031
@@ -19312,7 +19311,7 @@ comment: From DeltaMass: Average Mass: 118
 synonym: "diMeBzl" EXACT DeltaMass-label []
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01032
@@ -19324,7 +19323,7 @@ property_value: DiffFormula "C 8 H 8 O 1" xsd:string
 property_value: DiffMono "120.057515" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01033
@@ -19337,7 +19336,7 @@ property_value: DiffFormula "C 8 H 8 O 1" xsd:string
 property_value: DiffMono "120.057515" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01034
@@ -19350,7 +19349,7 @@ property_value: DiffFormula "C 6 H 3 N 1 O 2" xsd:string
 property_value: DiffMono "121.016378" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01035
@@ -19360,7 +19359,7 @@ comment: From DeltaMass: Average Mass: 125
 synonym: "ClBzl" EXACT DeltaMass-label []
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01036
@@ -19387,7 +19386,7 @@ property_value: MassAvg "232.06" xsd:float
 property_value: MassMono "230.985384" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00987
+is_a: MOD:00987 ! chlorinated tyrosine
 
 [Term]
 id: MOD:01038
@@ -19425,7 +19424,7 @@ property_value: MassAvg "131.19" xsd:float
 property_value: MassMono "131.040485" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00850
+is_a: MOD:00850 ! unnatural residue
 
 [Term]
 id: MOD:01041
@@ -19436,7 +19435,7 @@ property_value: DiffAvg "134.13" xsd:float
 property_value: DiffFormula "C 8 H 6 O 2" xsd:string
 property_value: DiffMono "134.036779" xsd:float
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01042
@@ -19447,7 +19446,7 @@ property_value: DiffAvg "134.22" xsd:float
 property_value: DiffFormula "C 10 H 14" xsd:string
 property_value: DiffMono "134.109550" xsd:float
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01043
@@ -19458,7 +19457,7 @@ property_value: DiffAvg "135.12" xsd:float
 property_value: DiffFormula "C 7 H 5 N 1 O 2" xsd:string
 property_value: DiffMono "135.032028" xsd:float
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01044
@@ -19482,7 +19481,7 @@ property_value: MassAvg "232.06" xsd:float
 property_value: MassMono "230.985384" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01037
+is_a: MOD:01037 ! dichlorinated tyrosine
 
 [Term]
 id: MOD:01046
@@ -19497,7 +19496,7 @@ property_value: MassAvg "197.62" xsd:float
 property_value: MassMono "197.024356" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01028
+is_a: MOD:01028 ! monochlorinated L-tyrosine
 
 [Term]
 id: MOD:01047
@@ -19518,8 +19517,8 @@ property_value: MassMono "144.089878" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:35
-is_a: MOD:00425
-is_a: MOD:00681
+is_a: MOD:00425 ! monohydroxylated residue
+is_a: MOD:00681 ! hydroxylated lysine
 
 [Term]
 id: MOD:01048
@@ -19533,8 +19532,8 @@ property_value: MassAvg "112.11" xsd:float
 property_value: MassMono "112.039853" xsd:float
 property_value: Origin "X" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00601
-is_a: MOD:00859
+is_a: MOD:00601 ! cyclized residue
+is_a: MOD:00859 ! modified residue that can arise from different natural residues
 
 [Term]
 id: MOD:01049
@@ -19542,8 +19541,8 @@ name: halogenated histidine
 def: "A protein modification that effectively substitutes a hydrogen atom of an L-histidine residue with a halogen atom." [PubMed:18688235]
 synonym: "HalHis" EXACT PSI-MOD-label []
 property_value: Origin "H" xsd:string
-is_a: MOD:00694
-is_a: MOD:00909
+is_a: MOD:00694 ! halogen containing residue
+is_a: MOD:00909 ! modified L-histidine residue
 
 [Term]
 id: MOD:01050
@@ -19552,7 +19551,7 @@ def: "modification from DeltaMass" [DeltaMass:180]
 comment: From DeltaMass: Average Mass: 148 Formula:C8H8O2N1 Monoisotopic Mass Change:148.064 Average Mass Change:148.165
 property_value: Origin "A" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01051
@@ -19561,7 +19560,7 @@ def: "modification from DeltaMass" [DeltaMass:0]
 comment: From DeltaMass: Average Mass: 149
 synonym: "NBz" EXACT DeltaMass-label []
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01052
@@ -19570,7 +19569,7 @@ def: "modification from DeltaMass" [DeltaMass:0]
 comment: From DeltaMass: Average Mass: 150
 property_value: Origin "W" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01053
@@ -19579,7 +19578,7 @@ def: "modification from DeltaMass" [DeltaMass:0]
 comment: From DeltaMass: Average Mass: 153
 synonym: "Nps" EXACT DeltaMass-label []
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01054
@@ -19590,7 +19589,7 @@ synonym: "4-toluenesulphonyl" EXACT DeltaMass-label []
 synonym: "Tos" EXACT DeltaMass-label []
 synonym: "Tosyl" EXACT DeltaMass-label []
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01055
@@ -19599,7 +19598,7 @@ def: "modification from DeltaMass" [DeltaMass:0]
 comment: From DeltaMass: Average Mass: 154
 synonym: "Npys" EXACT DeltaMass-label []
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01056
@@ -19614,8 +19613,8 @@ property_value: MassAvg "318.88" xsd:float
 property_value: MassMono "318.884353" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
-relationship: derives_from MOD:01023
-is_a: MOD:01006
+relationship: derives_from MOD:01023 ! 3',5'-dibromo-L-tyrosine
+is_a: MOD:01006 ! dibrominated tyrosine
 
 [Term]
 id: MOD:01057
@@ -19630,8 +19629,8 @@ property_value: MassAvg "320.88" xsd:float
 property_value: MassMono "320.882306" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
-relationship: derives_from MOD:01023
-is_a: MOD:01006
+relationship: derives_from MOD:01023 ! 3',5'-dibromo-L-tyrosine
+is_a: MOD:01006 ! dibrominated tyrosine
 
 [Term]
 id: MOD:01058
@@ -19640,7 +19639,7 @@ def: "modification from DeltaMass" [DeltaMass:0]
 comment: From DeltaMass: Average Mass: 159
 synonym: "Dcb" EXACT DeltaMass-label []
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01059
@@ -19655,8 +19654,8 @@ property_value: MassAvg "322.88" xsd:float
 property_value: MassMono "322.880260" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
-relationship: derives_from MOD:01023
-is_a: MOD:01006
+relationship: derives_from MOD:01023 ! 3',5'-dibromo-L-tyrosine
+is_a: MOD:01006 ! dibrominated tyrosine
 
 [Term]
 id: MOD:01060
@@ -19683,8 +19682,8 @@ property_value: MassMono "160.030649" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:4
-is_a: MOD:00397
-is_a: MOD:00905
+is_a: MOD:00397 ! iodoacetamide derivatized residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:01061
@@ -19707,8 +19706,8 @@ property_value: MassMono "161.014664" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:6
-is_a: MOD:00399
-is_a: MOD:00905
+is_a: MOD:00399 ! iodoacetic acid derivatized residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:01062
@@ -19738,15 +19737,15 @@ property_value: Formula "C 10 H 11 N 1 O 1" xsd:string
 property_value: MassAvg "161.20" xsd:float
 property_value: MassMono "161.084064" xsd:float
 property_value: Origin "F" xsd:string
-is_a: MOD:00599
-is_a: MOD:00717
+is_a: MOD:00599 ! monomethylated residue
+is_a: MOD:00717 ! methylated phenylalanine
 
 [Term]
 id: MOD:01064
 name: inositol
 def: "modification from DeltaMass" [DeltaMass:0]
 comment: From DeltaMass: Average Mass: 162
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01065
@@ -19758,7 +19757,7 @@ property_value: DiffFormula "C 6 H 10 O 5" xsd:string
 property_value: DiffMono "162.052823" xsd:float
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:41
-is_a: MOD:00767
+is_a: MOD:00767 ! glycated residue
 
 [Term]
 id: MOD:01066
@@ -19766,8 +19765,8 @@ name: halogenated phenylalanine
 def: "A protein modification that effectively substitutes a hydrogen atom of an L-phenylalanine residue with a halogen atom." [PubMed:18688235]
 synonym: "HalPhe" EXACT PSI-MOD-label []
 property_value: Origin "F" xsd:string
-is_a: MOD:00694
-is_a: MOD:00914
+is_a: MOD:00694 ! halogen containing residue
+is_a: MOD:00914 ! modified L-phenylalanine residue
 
 [Term]
 id: MOD:01067
@@ -19775,7 +19774,7 @@ name: linker attached to peptide in Fmoc peptide synthesis
 def: "modification from DeltaMass" [DeltaMass:341]
 comment: From DeltaMass: Average Mass: 162 Average Mass Change:162 Notes: (from the ABRF discussion list archive) There may be ... things in the reagent K that would allow cleavage of the peptide to occur at the wrong place...in this case it removes the dimethoxybenzyl group first inactivating that site for cleavage, and it goes after tne next amide bond closer to the resin. Try the TFA/TIS/water/EDT cocktail...TFA = 92%, TIS =3%, and water is at 5%. .. had this issue on longer peptides.. and by increasing the amount of water a little bit... able to elminate this problem.
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01068
@@ -19783,8 +19782,8 @@ name: halogenated tryptophan
 def: "A protein modification that effectively substitutes a hydrogen atom of an L-tryptophan residue with a halogen atom." [PubMed:18688235]
 synonym: "HalTrp" EXACT PSI-MOD-label []
 property_value: Origin "W" xsd:string
-is_a: MOD:00694
-is_a: MOD:00918
+is_a: MOD:00694 ! halogen containing residue
+is_a: MOD:00918 ! modified L-tryptophan residue
 
 [Term]
 id: MOD:01069
@@ -19795,7 +19794,7 @@ property_value: DiffAvg "166.09" xsd:float
 property_value: DiffFormula "C 6 H 2 N 2 O 4" xsd:string
 property_value: DiffMono "166.001457" xsd:float
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01070
@@ -19807,7 +19806,7 @@ property_value: DiffAvg "166.05" xsd:float
 property_value: DiffFormula "C 6 F 5 H -1" xsd:string
 property_value: DiffMono "165.984191" xsd:float
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01071
@@ -19819,7 +19818,7 @@ property_value: DiffFormula "C 13 H 10" xsd:string
 property_value: DiffMono "166.078250" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01072
@@ -19831,7 +19830,7 @@ property_value: DiffAvg "38.09" xsd:float
 property_value: DiffFormula "H -1 K 1" xsd:string
 property_value: DiffMono "37.955882" xsd:float
 property_value: Origin "X" xsd:string
-is_a: MOD:00849
+is_a: MOD:00849 ! potassium containing modified residue
 
 [Term]
 id: MOD:01073
@@ -19843,7 +19842,7 @@ property_value: DiffFormula "C 8 Cl 1 H 6 O 2" xsd:string
 property_value: DiffMono "169.005632" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01074
@@ -19854,14 +19853,14 @@ property_value: DiffFormula "C 12 H 9 O 1" xsd:string
 property_value: DiffMono "169.065340" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01075
 name: mercury containing modified residue
 def: "A protein modification that effectively substitutes a mercury atom or a cluster containing mercury for hydrogen atoms, or that coordinates a mercury ion." [PubMed:18688235]
 synonym: "HgRes" EXACT PSI-MOD-label []
-is_a: MOD:00698
+is_a: MOD:00698 ! metal or metal cluster containing modified residue
 
 [Term]
 id: MOD:01076
@@ -19881,7 +19880,7 @@ name: ethanedithiol/TFA cyclic adduct
 def: "modification from DeltaMass" [DeltaMass:216]
 comment: From DeltaMass: Average Mass: 172 Average Mass Change:172 References:[1]. Sieber,P.(1987) Modification of tryptophan residues during acidolysis of4-methoxy-2,3,6-trimethylbenzenesulfonyl groups. Effects of scavengers. Tetrahedron Lett., 28(15),1637-1640. Notes: TFA-cyclic dithioketal by-product is formed when Trp-containing peptide is subjected to prolonged TFA/EDT treatment [1]. See structure at http://www.abrf.org/images/misc/dmass172.gif. Additional discussion of this adduct, and how to avoid it, can befound in Methods in Enzymology 289, 67 (1997)
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01078
@@ -19901,7 +19900,7 @@ property_value: MassMono "160.067034" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:472
-is_a: MOD:00917
+is_a: MOD:00917 ! modified L-threonine residue
 
 [Term]
 id: MOD:01079
@@ -19920,8 +19919,8 @@ property_value: MassAvg "174.22" xsd:float
 property_value: MassMono "174.046299" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
-is_a: MOD:00905
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:01080
@@ -19945,7 +19944,7 @@ comment: From DeltaMass: Average Mass: 177. CAUTION - mass does not match formul
 property_value: DiffAvg "178.14" xsd:float
 property_value: DiffFormula "C 6 H 10 O 6" xsd:string
 property_value: DiffMono "178.047738" xsd:float
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01082
@@ -19974,8 +19973,8 @@ property_value: MassAvg "177.20" xsd:float
 property_value: MassMono "177.078979" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00916
-is_a: MOD:01008
+is_a: MOD:00916 ! modified L-serine residue
+is_a: MOD:01008 ! benzyl (Bzl) and benzyl ester (OBzl) modified residue
 
 [Term]
 id: MOD:01084
@@ -19992,7 +19991,7 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:6
-is_a: MOD:00399
+is_a: MOD:00399 ! iodoacetic acid derivatized residue
 
 [Term]
 id: MOD:01085
@@ -20008,8 +20007,8 @@ property_value: MassMono "316.114475" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00909
-is_a: MOD:00006
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:00006 ! N-glycosylated residue
 
 [Term]
 id: MOD:01086
@@ -20018,7 +20017,7 @@ def: "modification from DeltaMass" [DeltaMass:0]
 comment: From DeltaMass: Average Mass: 179
 synonym: "4Nz" EXACT DeltaMass-label []
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01087
@@ -20028,7 +20027,7 @@ property_value: DiffAvg "179.42" xsd:float
 property_value: DiffFormula "C 6 Cl 3 H 1" xsd:string
 property_value: DiffMono "177.914383" xsd:float
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01088
@@ -20040,7 +20039,7 @@ property_value: DiffFormula "C 10 H 12 O 3" xsd:string
 property_value: DiffMono "180.078644" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01089
@@ -20049,7 +20048,7 @@ def: "modification from DeltaMass" [DeltaMass:0]
 comment: From DeltaMass: Average Mass: 180
 synonym: "Xan" EXACT DeltaMass-label []
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01090
@@ -20066,7 +20065,7 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:4
-is_a: MOD:00397
+is_a: MOD:00397 ! iodoacetamide derivatized residue
 
 [Term]
 id: MOD:01091
@@ -20082,8 +20081,8 @@ property_value: MassAvg "181.62" xsd:float
 property_value: MassMono "181.029442" xsd:float
 property_value: Origin "F" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01066
-is_a: MOD:01911
+is_a: MOD:01066 ! halogenated phenylalanine
+is_a: MOD:01911 ! monochlorinated residue
 
 [Term]
 id: MOD:01092
@@ -20092,7 +20091,7 @@ def: "modification from DeltaMass" [DeltaMass:0]
 comment: From DeltaMass: Average Mass: 182
 synonym: "Mts" EXACT DeltaMass-label []
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01093
@@ -20104,7 +20103,7 @@ property_value: MassAvg "184.24" xsd:float
 property_value: MassMono "184.121178" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01094
@@ -20124,7 +20123,7 @@ property_value: MassMono "186.100442" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:6
-is_a: MOD:00399
+is_a: MOD:00399 ! iodoacetic acid derivatized residue
 
 [Term]
 id: MOD:01095
@@ -20150,8 +20149,8 @@ property_value: MassAvg "191.23" xsd:float
 property_value: MassMono "191.094629" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00917
-is_a: MOD:01008
+is_a: MOD:00917 ! modified L-threonine residue
+is_a: MOD:01008 ! benzyl (Bzl) and benzyl ester (OBzl) modified residue
 
 [Term]
 id: MOD:01097
@@ -20166,8 +20165,8 @@ property_value: MassAvg "193.26" xsd:float
 property_value: MassMono "193.056135" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00905
-is_a: MOD:01008
+is_a: MOD:00905 ! modified L-cysteine residue
+is_a: MOD:01008 ! benzyl (Bzl) and benzyl ester (OBzl) modified residue
 
 [Term]
 id: MOD:01098
@@ -20179,7 +20178,7 @@ property_value: MassAvg "197.24" xsd:float
 property_value: MassMono "197.084064" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00850
+is_a: MOD:00850 ! unnatural residue
 
 [Term]
 id: MOD:01099
@@ -20196,7 +20195,7 @@ property_value: MassMono "198.040247" xsd:float
 property_value: Origin "D" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00904
+is_a: MOD:00904 ! modified L-aspartic acid residue
 
 [Term]
 id: MOD:01100
@@ -20204,7 +20203,7 @@ name: HMP (hydroxymethylphenyl)/TFA adduct
 def: "modification from DeltaMass" [DeltaMass:0]
 comment: From DeltaMass: Average Mass: 201 with no citation.
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01101
@@ -20239,7 +20238,7 @@ def: "modification from DeltaMass" [DeltaMass:0]
 comment: From DeltaMass: Average Mass: 212 with no citation.
 synonym: "Mtr" EXACT DeltaMass-label []
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01105
@@ -20248,7 +20247,7 @@ def: "modification from DeltaMass" [DeltaMass:0]
 comment: From DeltaMass: Average Mass: 213 with no citation.
 synonym: "BrZ" EXACT DeltaMass-label []
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01106
@@ -20264,8 +20263,8 @@ property_value: MassAvg "214.22" xsd:float
 property_value: MassMono "214.074228" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00409
-is_a: MOD:00918
+is_a: MOD:00409 ! N-formylated residue
+is_a: MOD:00918 ! modified L-tryptophan residue
 
 [Term]
 id: MOD:01107
@@ -20280,8 +20279,8 @@ property_value: MassAvg "219.24" xsd:float
 property_value: MassMono "219.089543" xsd:float
 property_value: Origin "E" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00906
-is_a: MOD:01008
+is_a: MOD:00906 ! modified L-glutamic acid residue
+is_a: MOD:01008 ! benzyl (Bzl) and benzyl ester (OBzl) modified residue
 
 [Term]
 id: MOD:01108
@@ -20297,8 +20296,8 @@ property_value: MassAvg "219.24" xsd:float
 property_value: MassMono "219.089543" xsd:float
 property_value: Origin "E" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00906
-is_a: MOD:01007
+is_a: MOD:00906 ! modified L-glutamic acid residue
+is_a: MOD:01007 ! anisyl modified residue
 
 [Term]
 id: MOD:01109
@@ -20306,7 +20305,7 @@ name: 9-fluorenylmethyloxycarbonyl (Fmoc)
 def: "modification from DeltaMass" [DeltaMass:0]
 comment: From DeltaMass: Average Mass: 222 with no citation.
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01110
@@ -20315,8 +20314,8 @@ def: "A protein modification that effectively replaces a hydrogen atom of an L-c
 subset: PSI-MOD-slim
 synonym: "IpCys" EXACT PSI-MOD-label []
 property_value: Origin "C" xsd:string
-is_a: MOD:00703
-is_a: MOD:00905
+is_a: MOD:00703 ! isoprenylated residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:01111
@@ -20330,7 +20329,7 @@ property_value: DiffAvg "226.27" xsd:float
 property_value: DiffFormula "C 15 H 14 O 2" xsd:string
 property_value: DiffMono "226.099380" xsd:float
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01112
@@ -20346,7 +20345,7 @@ property_value: MassAvg "233.27" xsd:float
 property_value: MassMono "233.116427" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01113
@@ -20355,7 +20354,7 @@ def: "modification from DeltaMass" [DeltaMass:0]
 comment: From DeltaMass: Average Mass: 238 with no citation.
 synonym: "Bpoc" EXACT DeltaMass-label []
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01114
@@ -20368,7 +20367,7 @@ property_value: DiffAvg "242.32" xsd:float
 property_value: DiffFormula "C 19 H 14" xsd:string
 property_value: DiffMono "242.109550" xsd:float
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01115
@@ -20376,8 +20375,8 @@ name: isoprenylated tryptophan
 def: "A protein modification that effectively replaces a hydrogen atom of an L-tryptophan residue with a group derived from an isoprene polymer, such as a geranyl (C10), farnesyl (C15) or geranylgeranyl (C20)." [PubMed:18688235]
 synonym: "IpTrp" EXACT PSI-MOD-label []
 property_value: Origin "W" xsd:string
-is_a: MOD:00703
-is_a: MOD:00918
+is_a: MOD:00703 ! isoprenylated residue
+is_a: MOD:00918 ! modified L-tryptophan residue
 
 [Term]
 id: MOD:01116
@@ -20394,9 +20393,9 @@ property_value: MassMono "338.215375" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
-is_a: MOD:00905
-relationship: has_functional_parent MOD:00111
-relationship: has_functional_parent MOD:00114
+is_a: MOD:00905 ! modified L-cysteine residue
+relationship: has_functional_parent MOD:00111 ! S-farnesyl-L-cysteine
+relationship: has_functional_parent MOD:00114 ! L-cysteine methyl ester
 
 [Term]
 id: MOD:01117
@@ -20405,7 +20404,7 @@ def: "modification from DeltaMass" [DeltaMass:0]
 comment: From DeltaMass: Average Mass: 252 with no citation.
 synonym: "Pbf" EXACT DeltaMass-label []
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01118
@@ -20421,8 +20420,8 @@ property_value: MassMono "396.080806" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00909
-is_a: MOD:00006
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:00006 ! N-glycosylated residue
 
 [Term]
 id: MOD:01119
@@ -20439,9 +20438,9 @@ property_value: MassMono "406.277976" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
-is_a: MOD:00905
-relationship: has_functional_parent MOD:00113
-relationship: has_functional_parent MOD:00114
+is_a: MOD:00905 ! modified L-cysteine residue
+relationship: has_functional_parent MOD:00113 ! S-geranylgeranyl-L-cysteine
+relationship: has_functional_parent MOD:00114 ! L-cysteine methyl ester
 
 [Term]
 id: MOD:01120
@@ -20461,7 +20460,7 @@ property_value: DiffFormula "C 14 H 18 O 3 S 1" xsd:string
 property_value: DiffMono "266.097665" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01652
+is_a: MOD:01652 ! sulfonyl halide reagent derivatized residue
 
 [Term]
 id: MOD:01121
@@ -20470,7 +20469,7 @@ def: "modification from DeltaMass" [DeltaMass:280]
 comment: From DeltaMass: Average Mass: 272 Average Mass Change: 272
 synonym: "Mmt" EXACT DeltaMass-label []
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01122
@@ -20500,7 +20499,7 @@ property_value: Formula "C 12 H 22 N 2 O 6" xsd:string
 property_value: MassAvg "290.32" xsd:float
 property_value: MassMono "290.147786" xsd:float
 property_value: Origin "K" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01125
@@ -20530,7 +20529,7 @@ name: N-glycolneuraminic acid
 def: "modification from DeltaMass" [DeltaMass:0]
 comment: From DeltaMass: Average Mass: 307 with no citation.
 synonym: "NeuGc" EXACT DeltaMass-label []
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01129
@@ -20545,7 +20544,7 @@ name: SucPhencarb Lysyl
 def: "modification from DeltaMass" [DeltaMass:297]
 comment: From DeltaMass: Average Mass: 327 Formula: C17H17O3N4 Monoisotopic Mass Change: 327.122 Average Mass Change: 327.342
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01131
@@ -20576,9 +20575,9 @@ property_value: MassMono "354.210290" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
-is_a: MOD:00905
-relationship: has_functional_parent MOD:00112
-relationship: has_functional_parent MOD:00114
+is_a: MOD:00905 ! modified L-cysteine residue
+relationship: has_functional_parent MOD:00112 ! S-12-hydroxyfarnesyl-L-cysteine
+relationship: has_functional_parent MOD:00114 ! L-cysteine methyl ester
 
 [Term]
 id: MOD:01134
@@ -20586,14 +20585,14 @@ name: fluorescein labelling of peptide N-terminal using NHS ester
 def: "modification from DeltaMass" [DeltaMass:306]
 comment: From DeltaMass: Average Mass: 359 Formula: C21H11O6 Monoisotopic Mass Change: 359.055 Average Mass Change: 359.315 Notes: Using the DHB matrix at low pH the carboxyl group and one of the oxygens on the flurorescein molecule are protinated so the delta mass is 2Da higher than most text book illustrations would indicate. See Bioconjugate Techniques by Greg Hermanson, Academic Press, page 305, figure 204. Text books of course just show the coupling reaction at neutral or basic pH.
 property_value: Source "artifact" xsd:string
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01135
 name: Hex-HexNAc
 def: "modification from DeltaMass" [DeltaMass:0]
 comment: From DeltaMass: Average Mass: 365 with no citation.
-is_a: MOD:00947
+is_a: MOD:00947 ! DeltaMass
 
 [Term]
 id: MOD:01136
@@ -20618,8 +20617,8 @@ property_value: MassAvg "394.53" xsd:float
 property_value: MassMono "394.192628" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00902
-is_a: MOD:01120
+is_a: MOD:00902 ! modified L-arginine residue
+is_a: MOD:01120 ! 2,2,5,7,8-pentamethylchroman-6-sulfonyl chloride derivatized residue
 
 [Term]
 id: MOD:01138
@@ -20657,8 +20656,8 @@ property_value: MassMono "414.856624" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:130
-is_a: MOD:00501
-is_a: MOD:00998
+is_a: MOD:00501 ! diiodinated residue
+is_a: MOD:00998 ! iodinated tyrosine
 
 [Term]
 id: MOD:01141
@@ -20675,8 +20674,8 @@ property_value: MassAvg "422.54" xsd:float
 property_value: MassMono "422.198776" xsd:float
 property_value: Origin "R" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00902
-is_a: MOD:01120
+is_a: MOD:00902 ! modified L-arginine residue
+is_a: MOD:01120 ! 2,2,5,7,8-pentamethylchroman-6-sulfonyl chloride derivatized residue
 
 [Term]
 id: MOD:01142
@@ -20700,8 +20699,8 @@ property_value: MassAvg "687.81" xsd:float
 property_value: MassMono "687.272670" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00700
-is_a: MOD:00905
+is_a: MOD:00700 ! tetrapyrrole modified residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:01143
@@ -20726,8 +20725,8 @@ property_value: MassAvg "790.95" xsd:float
 property_value: MassMono "790.281854" xsd:float
 property_value: Origin "C, C" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00700
-is_a: MOD:02044
+is_a: MOD:00700 ! tetrapyrrole modified residue
+is_a: MOD:02044 ! crosslinked L-cysteine residue
 
 [Term]
 id: MOD:01144
@@ -20744,7 +20743,7 @@ property_value: MassAvg "654.05" xsd:float
 property_value: MassMono "653.505295" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00116
+is_a: MOD:00116 ! S-diacylglycerol-L-cysteine
 
 [Term]
 id: MOD:01145
@@ -20762,9 +20761,9 @@ property_value: MassMono "821.237910" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0672
-is_a: MOD:02087
-is_a: MOD:00909
-relationship: derives_from MOD:00049
+is_a: MOD:02087 ! adenosine diphosphoribosyl (ADP-ribosyl) modified residue
+is_a: MOD:00909 ! modified L-histidine residue
+relationship: derives_from MOD:00049 ! 2'-[3-carboxamido-3-(trimethylammonio)propyl]-L-histidine
 
 [Term]
 id: MOD:01146
@@ -20782,8 +20781,8 @@ property_value: MassAvg "886.68" xsd:float
 property_value: MassMono "886.150669" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "hypothetical" xsd:string
-is_a: MOD:00895
-is_a: MOD:00905
+is_a: MOD:00895 ! FAD modified residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:01147
@@ -20800,8 +20799,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:1761
 xref: GNO:G20956ZV
-is_a: MOD:00725
-is_a: MOD:00160
+is_a: MOD:00725 ! complex glycosylation
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:01148
@@ -20810,10 +20809,10 @@ def: "A protein modification that effectively crosslinks the N6-amino of a pepti
 subset: PSI-MOD-slim
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:02047
-is_a: MOD:02051
-is_a: MOD:01875
-relationship: contains MOD:00134
+is_a: MOD:02047 ! crosslinked glycine residue
+is_a: MOD:02051 ! crosslinked L-lysine residue
+is_a: MOD:01875 ! N6-acylated L-lysine
+relationship: contains MOD:00134 ! N6-glycyl-L-lysine
 
 [Term]
 id: MOD:01149
@@ -20822,10 +20821,10 @@ def: "A protein modification that effectively crosslinks the N6-amino of a pepti
 subset: PSI-MOD-slim
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:02047
-is_a: MOD:02051
-is_a: MOD:01875
-relationship: contains MOD:00134
+is_a: MOD:02047 ! crosslinked glycine residue
+is_a: MOD:02051 ! crosslinked L-lysine residue
+is_a: MOD:01875 ! N6-acylated L-lysine
+relationship: contains MOD:00134 ! N6-glycyl-L-lysine
 
 [Term]
 id: MOD:01150
@@ -20834,10 +20833,10 @@ def: "A protein modification that effectively crosslinks the N6-amino of a pepti
 subset: PSI-MOD-slim
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:02051
-is_a: MOD:02047
-is_a: MOD:01875
-relationship: contains MOD:00134
+is_a: MOD:02051 ! crosslinked L-lysine residue
+is_a: MOD:02047 ! crosslinked glycine residue
+is_a: MOD:01875 ! N6-acylated L-lysine
+relationship: contains MOD:00134 ! N6-glycyl-L-lysine
 
 [Term]
 id: MOD:01151
@@ -20849,7 +20848,7 @@ property_value: DiffFormula "C 0 H -3 N 0 O -4 P -1" xsd:string
 property_value: DiffMono "-97.976895" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00432
+is_a: MOD:00432 ! modified residue with neutral loss of phosphate
 
 [Term]
 id: MOD:01152
@@ -20863,7 +20862,7 @@ property_value: DiffFormula "C 1 H 0 N 0 O 2" xsd:string
 property_value: DiffMono "43.989829" xsd:float
 property_value: Origin "X" xsd:string
 xref: Unimod:299
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:01153
@@ -20877,7 +20876,7 @@ property_value: DiffFormula "C 1 H 2 N 0 O 0 S 1" xsd:string
 property_value: DiffMono "45.987721" xsd:float
 property_value: Origin "X" xsd:string
 xref: Unimod:39
-is_a: MOD:01886
+is_a: MOD:01886 ! thiolated residue
 
 [Term]
 id: MOD:01154
@@ -20893,29 +20892,29 @@ property_value: MassAvg "71.06" xsd:float
 property_value: MassMono "71.013304" xsd:float
 property_value: Origin "X" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00769
-is_a: MOD:00859
+is_a: MOD:00769 ! residues isobaric at 71.0-71.1 Da
+is_a: MOD:00859 ! modified residue that can arise from different natural residues
 
 [Term]
 id: MOD:01155
 name: lipoconjugated residue
 def: "A protein modification that effectively results from forming an adduct with a compound containing a lipid-like group either through acylation, alkylation, or amidation." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:01156
 name: protein modification categorized by chemical process
 def: "Modified amino acid residue derived from a natural amino acid by a real or hypothetical chemical process." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00000
+is_a: MOD:00000 ! protein modification
 
 [Term]
 id: MOD:01157
 name: protein modification categorized by amino acid modified
 def: "A protein modification considered either as modified amino acid residues derived from natural amino acids, as a replacement by another natural amino acid, or as a replacement by an unnatural amino acid." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00000
+is_a: MOD:00000 ! protein modification
 
 [Term]
 id: MOD:01158
@@ -20923,9 +20922,9 @@ name: modified L-selenocysteine residue
 def: "A protein modification that modifies an L-selenocysteine residue." [PubMed:18688235]
 subset: PSI-MOD-slim
 property_value: Origin "U" xsd:string
-is_a: MOD:00745
-is_a: MOD:01157
-relationship: derives_from MOD:00031
+is_a: MOD:00745 ! selenium containing residue
+is_a: MOD:01157 ! protein modification categorized by amino acid modified
+relationship: derives_from MOD:00031 ! L-selenocysteine residue
 
 [Term]
 id: MOD:01159
@@ -20933,7 +20932,7 @@ name: peptidoglycanated residue
 def: "A protein modification that effectively attaches a residue to murein peptidoglycan by either a pentaglycine linker peptide or a peptide-like L-alanyl-D-glutamyl-2,6-diaminopimelic acid linkage." [PubMed:18688235]
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00764
+is_a: MOD:00764 ! glycoconjugated residue
 
 [Term]
 id: MOD:01160
@@ -20947,7 +20946,7 @@ property_value: DiffFormula "C 0 H -3 N -1 O 0" xsd:string
 property_value: DiffMono "-17.026549" xsd:float
 property_value: Origin "X" xsd:string
 xref: Unimod:385
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:01161
@@ -20962,7 +20961,7 @@ property_value: DiffFormula "C 0 H 0 N 0 O -1" xsd:string
 property_value: DiffMono "-15.994915" xsd:float
 property_value: Origin "X" xsd:string
 xref: Unimod:447
-is_a: MOD:01472
+is_a: MOD:01472 ! reduced residue
 
 [Term]
 id: MOD:01162
@@ -20980,7 +20979,7 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:308
 xref: GNO:G83555HU
-is_a: MOD:00725
+is_a: MOD:00725 ! complex glycosylation
 
 [Term]
 id: MOD:01163
@@ -20995,7 +20994,7 @@ property_value: DiffFormula "C 10 H 12 N 5 O 7 P 1" xsd:string
 property_value: DiffMono "345.047434" xsd:float
 property_value: Origin "X" xsd:string
 xref: Unimod:413
-is_a: MOD:00701
+is_a: MOD:00701 ! nucleotide or nucleic acid modified residue
 
 [Term]
 id: MOD:01164
@@ -21009,7 +21008,7 @@ property_value: DiffFormula "C 17 H 19 N 4 O 8 P 1" xsd:string
 property_value: DiffMono "438.094050" xsd:float
 property_value: Origin "X" xsd:string
 xref: Unimod:442
-is_a: MOD:00697
+is_a: MOD:00697 ! flavin modified residue
 
 [Term]
 id: MOD:01165
@@ -21025,7 +21024,7 @@ property_value: DiffFormula "C 10 H 12 N 5 O 6 P 1" xsd:string
 property_value: DiffMono "329.052520" xsd:float
 property_value: Origin "X" xsd:string
 xref: Unimod:405
-is_a: MOD:00701
+is_a: MOD:00701 ! nucleotide or nucleic acid modified residue
 
 [Term]
 id: MOD:01166
@@ -21040,7 +21039,7 @@ property_value: DiffFormula "C 9 H 11 N 2 O 8 P 1" xsd:string
 property_value: DiffMono "306.025302" xsd:float
 property_value: Origin "X" xsd:string
 xref: Unimod:417
-is_a: MOD:00701
+is_a: MOD:00701 ! nucleotide or nucleic acid modified residue
 
 [Term]
 id: MOD:01167
@@ -21053,7 +21052,7 @@ property_value: DiffFormula "C 40 H 47 Mo 1 N 20 O 26 P 4 S 4" xsd:string
 property_value: DiffMono "1572.985775" xsd:float
 property_value: Origin "X" xsd:string
 xref: Unimod:424
-is_a: MOD:00744
+is_a: MOD:00744 ! molybdenum pterin containing modification
 
 [Term]
 id: MOD:01168
@@ -21075,7 +21074,7 @@ property_value: MassAvg "69.06" xsd:float
 property_value: MassMono "69.021464" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00859
+is_a: MOD:00859 ! modified residue that can arise from different natural residues
 
 [Term]
 id: MOD:01169
@@ -21096,7 +21095,7 @@ property_value: MassAvg "85.06" xsd:float
 property_value: MassMono "85.016378" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00859
+is_a: MOD:00859 ! modified residue that can arise from different natural residues
 
 [Term]
 id: MOD:01170
@@ -21110,7 +21109,7 @@ property_value: DiffMono "70.005479" xsd:float
 property_value: Origin "X" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:422
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:01171
@@ -21135,8 +21134,8 @@ property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:1
 xref: uniprot.ptm:PTM-0233
-is_a: MOD:00644
-is_a: MOD:01186
+is_a: MOD:00644 ! mono O-acetylated residue
+is_a: MOD:01186 ! monoacetylated L-threonine
 
 [Term]
 id: MOD:01172
@@ -21155,8 +21154,8 @@ property_value: Origin "A" xsd:string
 property_value: Source "hypothetical" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0144
-is_a: MOD:00466
-is_a: MOD:00901
+is_a: MOD:00466 ! glycosylsphingolipidinositolated residue
+is_a: MOD:00901 ! modified L-alanine residue
 
 [Term]
 id: MOD:01173
@@ -21175,8 +21174,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "hypothetical" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0145
-is_a: MOD:00466
-is_a: MOD:00903
+is_a: MOD:00466 ! glycosylsphingolipidinositolated residue
+is_a: MOD:00903 ! modified L-asparagine residue
 
 [Term]
 id: MOD:01174
@@ -21196,8 +21195,8 @@ property_value: MassMono "419.213030" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0447
-is_a: MOD:00905
-is_a: MOD:01155
+is_a: MOD:00905 ! modified L-cysteine residue
+is_a: MOD:01155 ! lipoconjugated residue
 
 [Term]
 id: MOD:01175
@@ -21218,8 +21217,8 @@ property_value: MassAvg "689.83" xsd:float
 property_value: MassMono "689.288320" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00700
-is_a: MOD:00905
+is_a: MOD:00700 ! tetrapyrrole modified residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:01176
@@ -21243,8 +21242,8 @@ property_value: MassAvg "237.30" xsd:float
 property_value: MassMono "237.147727" xsd:float
 property_value: Origin "K, K" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00692
-is_a: MOD:02051
+is_a: MOD:00692 ! uncategorized crosslinked residues
+is_a: MOD:02051 ! crosslinked L-lysine residue
 
 [Term]
 id: MOD:01177
@@ -21267,7 +21266,7 @@ property_value: MassMono "227.090606" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0416
-is_a: MOD:00909
+is_a: MOD:00909 ! modified L-histidine residue
 
 [Term]
 id: MOD:01178
@@ -21287,7 +21286,7 @@ property_value: MassAvg "191.16" xsd:float
 property_value: MassMono "190.988843" xsd:float
 property_value: Origin "D" xsd:string
 property_value: Source "hypothetical" xsd:string
-is_a: MOD:00904
+is_a: MOD:00904 ! modified L-aspartic acid residue
 
 [Term]
 id: MOD:01179
@@ -21309,8 +21308,8 @@ property_value: Origin "A" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0178
-is_a: MOD:01461
-is_a: MOD:01686
+is_a: MOD:01461 ! N-methylated alanine
+is_a: MOD:01686 ! alpha-amino dimethylated residue
 
 [Term]
 id: MOD:01180
@@ -21330,8 +21329,8 @@ property_value: MassAvg "73.05" xsd:float
 property_value: MassMono "73.016378" xsd:float
 property_value: Origin "G" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00425
-is_a: MOD:00908
+is_a: MOD:00425 ! monohydroxylated residue
+is_a: MOD:00908 ! modified glycine residue
 
 [Term]
 id: MOD:01181
@@ -21358,8 +21357,8 @@ property_value: MassMono "129.042593" xsd:float
 property_value: Origin "D" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:34
-is_a: MOD:00393
-is_a: MOD:01681
+is_a: MOD:00393 ! O-methylated residue
+is_a: MOD:01681 ! monomethylated L-aspartic acid
 
 [Term]
 id: MOD:01182
@@ -21386,9 +21385,9 @@ property_value: MassMono "1021.193931" xsd:float
 property_value: Origin "C, H" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0681
-is_a: MOD:02044
-is_a: MOD:02048
-is_a: MOD:01621
+is_a: MOD:02044 ! crosslinked L-cysteine residue
+is_a: MOD:02048 ! crosslinked L-histidine residue
+is_a: MOD:01621 ! flavin crosslinked residues
 
 [Term]
 id: MOD:01183
@@ -21417,8 +21416,8 @@ property_value: MassAvg "298.08" xsd:float
 property_value: MassMono "299.891620" xsd:float
 property_value: Origin "U, U" xsd:string
 property_value: Source "hypothetical" xsd:string
-is_a: MOD:00692
-is_a: MOD:01158
+is_a: MOD:00692 ! uncategorized crosslinked residues
+is_a: MOD:01158 ! modified L-selenocysteine residue
 
 [Term]
 id: MOD:01184
@@ -21446,7 +21445,7 @@ property_value: MassAvg "298.08" xsd:float
 property_value: MassMono "299.891620" xsd:float
 property_value: Origin "C, C" xsd:string
 property_value: Source "hypothetical" xsd:string
-is_a: MOD:00905
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:01185
@@ -21475,8 +21474,8 @@ property_value: MassAvg "114.10" xsd:float
 property_value: MassMono "114.042927" xsd:float
 property_value: Origin "D" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00674
-is_a: MOD:00904
+is_a: MOD:00674 ! amidated residue
+is_a: MOD:00904 ! modified L-aspartic acid residue
 
 [Term]
 id: MOD:01186
@@ -21489,8 +21488,8 @@ property_value: DiffFormula "C 2 H 2 N 0 O 1" xsd:string
 property_value: DiffMono "42.010565" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00394
-is_a: MOD:00917
+is_a: MOD:00394 ! monoacetylated residue
+is_a: MOD:00917 ! modified L-threonine residue
 
 [Term]
 id: MOD:01187
@@ -21515,7 +21514,7 @@ property_value: MassMono "237.147727" xsd:float
 property_value: Origin "O" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:435
-is_a: MOD:00868
+is_a: MOD:00868 ! natural, non-standard encoded residue
 
 [Term]
 id: MOD:01188
@@ -21532,7 +21531,7 @@ property_value: MassMono "253.147476" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:212
-is_a: MOD:00562
+is_a: MOD:00562 ! N-ethyl iodoacetamide-d5
 
 [Term]
 id: MOD:01189
@@ -21549,7 +21548,7 @@ property_value: MassMono "193.093332" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:212
-is_a: MOD:00562
+is_a: MOD:00562 ! N-ethyl iodoacetamide-d5
 
 [Term]
 id: MOD:01190
@@ -21580,7 +21579,7 @@ property_value: MassMono "188.061949" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:211
-is_a: MOD:00561
+is_a: MOD:00561 ! N-ethyl iodoacetamide-d0
 
 [Term]
 id: MOD:01192
@@ -21597,7 +21596,7 @@ property_value: MassMono "248.116092" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:211
-is_a: MOD:00561
+is_a: MOD:00561 ! N-ethyl iodoacetamide-d0
 
 [Term]
 id: MOD:01193
@@ -21614,8 +21613,8 @@ property_value: MassMono "222.082684" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:264
-is_a: MOD:00917
-is_a: MOD:00586
+is_a: MOD:00917 ! modified L-threonine residue
+is_a: MOD:00586 ! pyridyl thiol modified residue
 
 [Term]
 id: MOD:01194
@@ -21632,8 +21631,8 @@ property_value: MassMono "208.067034" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:264
-is_a: MOD:00916
-is_a: MOD:00586
+is_a: MOD:00916 ! modified L-serine residue
+is_a: MOD:00586 ! pyridyl thiol modified residue
 
 [Term]
 id: MOD:01195
@@ -21650,7 +21649,7 @@ property_value: MassMono "232.121178" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:136
-is_a: MOD:00505
+is_a: MOD:00505 ! benzoyl labeling reagent light form (N-term and K)
 
 [Term]
 id: MOD:01196
@@ -21686,7 +21685,7 @@ property_value: MassMono "320.121966" xsd:float
 property_value: Origin "Q" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:490
-is_a: MOD:00925
+is_a: MOD:00925 ! heptosylated residue
 
 [Term]
 id: MOD:01198
@@ -21704,7 +21703,7 @@ property_value: MassMono "279.095417" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:490
-is_a: MOD:00925
+is_a: MOD:00925 ! heptosylated residue
 
 [Term]
 id: MOD:01199
@@ -21722,7 +21721,7 @@ property_value: MassMono "348.164499" xsd:float
 property_value: Origin "R" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:490
-is_a: MOD:00925
+is_a: MOD:00925 ! heptosylated residue
 
 [Term]
 id: MOD:01200
@@ -21740,7 +21739,7 @@ property_value: MassMono "293.111067" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:490
-is_a: MOD:00925
+is_a: MOD:00925 ! heptosylated residue
 
 [Term]
 id: MOD:01201
@@ -21758,7 +21757,7 @@ property_value: MassMono "320.158351" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:490
-is_a: MOD:00925
+is_a: MOD:00925 ! heptosylated residue
 
 [Term]
 id: MOD:01202
@@ -21776,7 +21775,7 @@ property_value: MassMono "306.106316" xsd:float
 property_value: Origin "N" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:490
-is_a: MOD:00925
+is_a: MOD:00925 ! heptosylated residue
 
 [Term]
 id: MOD:01203
@@ -21794,8 +21793,8 @@ property_value: MassMono "247.132077" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:25
-is_a: MOD:00418
-is_a: MOD:01875
+is_a: MOD:00418 ! pyridylacetylated residue
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01204
@@ -21812,7 +21811,7 @@ property_value: MassMono "83.037114" xsd:float
 property_value: Origin "M" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:526
-is_a: MOD:00913
+is_a: MOD:00913 ! modified L-methionine residue
 
 [Term]
 id: MOD:01205
@@ -21829,8 +21828,8 @@ property_value: MassMono "1034.355057" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:160
-is_a: MOD:00528
-is_a: MOD:00916
+is_a: MOD:00528 ! Hex1HexNAc1NeuAc2 glycosylated residue
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:01206
@@ -21847,8 +21846,8 @@ property_value: MassMono "1048.370707" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:160
-is_a: MOD:00528
-is_a: MOD:00005
+is_a: MOD:00528 ! Hex1HexNAc1NeuAc2 glycosylated residue
+is_a: MOD:00005 ! O-glycosyl-L-threonine
 
 [Term]
 id: MOD:01207
@@ -21865,8 +21864,8 @@ property_value: MassMono "1061.365956" xsd:float
 property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:160
-is_a: MOD:00528
-is_a: MOD:00160
+is_a: MOD:00528 ! Hex1HexNAc1NeuAc2 glycosylated residue
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:01208
@@ -21881,7 +21880,7 @@ property_value: DiffMono "61.921772" xsd:float
 property_value: Origin "X" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: Unimod:531
-is_a: MOD:00742
+is_a: MOD:00742 ! copper containing modified residue
 
 [Term]
 id: MOD:01209
@@ -21898,8 +21897,8 @@ property_value: MassAvg "177.63" xsd:float
 property_value: MassMono "176.948715" xsd:float
 property_value: Origin "D" xsd:string
 xref: Unimod:531
-is_a: MOD:00742
-is_a: MOD:02066
+is_a: MOD:00742 ! copper containing modified residue
+is_a: MOD:02066 ! metal or metal cluster coordinated L-aspartic acid residue
 
 [Term]
 id: MOD:01210
@@ -21916,8 +21915,8 @@ property_value: MassAvg "191.65" xsd:float
 property_value: MassMono "190.964366" xsd:float
 property_value: Origin "E" xsd:string
 xref: Unimod:531
-is_a: MOD:00742
-is_a: MOD:02068
+is_a: MOD:00742 ! copper containing modified residue
+is_a: MOD:02068 ! metal or metal cluster coordinated L-glutamic acid residue
 
 [Term]
 id: MOD:01211
@@ -21936,8 +21935,8 @@ property_value: MassMono "255.158292" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:29
-is_a: MOD:01813
-is_a: MOD:01875
+is_a: MOD:01813 ! morpholine-2-acetylated residue
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01212
@@ -21958,8 +21957,8 @@ property_value: MassMono "185.116427" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:4
-is_a: MOD:00397
-is_a: MOD:00912
+is_a: MOD:00397 ! iodoacetamide derivatized residue
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:01213
@@ -21978,8 +21977,8 @@ property_value: MassMono "194.080376" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:4
-is_a: MOD:00397
-is_a: MOD:00909
+is_a: MOD:00397 ! iodoacetamide derivatized residue
+is_a: MOD:00909 ! modified L-histidine residue
 
 [Term]
 id: MOD:01214
@@ -22013,8 +22012,8 @@ property_value: MassMono "172.048407" xsd:float
 property_value: Origin "D" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:4
-is_a: MOD:00397
-is_a: MOD:00904
+is_a: MOD:00397 ! iodoacetamide derivatized residue
+is_a: MOD:00904 ! modified L-aspartic acid residue
 
 [Term]
 id: MOD:01216
@@ -22033,8 +22032,8 @@ property_value: MassMono "186.064057" xsd:float
 property_value: Origin "E" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:4
-is_a: MOD:00397
-is_a: MOD:00906
+is_a: MOD:00397 ! iodoacetamide derivatized residue
+is_a: MOD:00906 ! modified L-glutamic acid residue
 
 [Term]
 id: MOD:01217
@@ -22051,7 +22050,7 @@ property_value: MassMono "270.031042" xsd:float
 property_value: Origin "D" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:285
-is_a: MOD:00605
+is_a: MOD:00605 ! Sulfanilic Acid (SA), light C12
 
 [Term]
 id: MOD:01218
@@ -22068,7 +22067,7 @@ property_value: MassMono "284.046692" xsd:float
 property_value: Origin "E" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:285
-is_a: MOD:00605
+is_a: MOD:00605 ! Sulfanilic Acid (SA), light C12
 
 [Term]
 id: MOD:01219
@@ -22085,7 +22084,7 @@ property_value: MassMono "276.051171" xsd:float
 property_value: Origin "D" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:286
-is_a: MOD:00606
+is_a: MOD:00606 ! Sulfanilic Acid (SA), heavy C13
 
 [Term]
 id: MOD:01220
@@ -22102,7 +22101,7 @@ property_value: MassMono "290.066822" xsd:float
 property_value: Origin "E" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:286
-is_a: MOD:00606
+is_a: MOD:00606 ! Sulfanilic Acid (SA), heavy C13
 
 [Term]
 id: MOD:01221
@@ -22120,8 +22119,8 @@ property_value: MassMono "129.042593" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:122
-is_a: MOD:02004
-is_a: MOD:01483
+is_a: MOD:02004 ! O3-acylated L-threonine
+is_a: MOD:01483 ! O-formylated residue
 
 [Term]
 id: MOD:01222
@@ -22139,8 +22138,8 @@ property_value: MassMono "115.026943" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:122
-is_a: MOD:02003
-is_a: MOD:01483
+is_a: MOD:02003 ! O3-acylated L-serine
+is_a: MOD:01483 ! O-formylated residue
 
 [Term]
 id: MOD:01223
@@ -22158,7 +22157,7 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:126
-is_a: MOD:00497
+is_a: MOD:00497 ! 3-sulfanylpropanoyl (N-term and Lys)
 
 [Term]
 id: MOD:01224
@@ -22178,7 +22177,7 @@ property_value: MassMono "216.093249" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:126
-is_a: MOD:00497
+is_a: MOD:00497 ! 3-sulfanylpropanoyl (N-term and Lys)
 
 [Term]
 id: MOD:01225
@@ -22197,8 +22196,8 @@ property_value: MassMono "181.053907" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:127
-is_a: MOD:00498
-is_a: MOD:00985
+is_a: MOD:00498 ! fluorinated residue
+is_a: MOD:00985 ! halogenated tyrosine
 
 [Term]
 id: MOD:01226
@@ -22216,8 +22215,8 @@ property_value: MassMono "204.069891" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:127
-is_a: MOD:00498
-is_a: MOD:01068
+is_a: MOD:00498 ! fluorinated residue
+is_a: MOD:01068 ! halogenated tryptophan
 
 [Term]
 id: MOD:01227
@@ -22236,8 +22235,8 @@ property_value: MassMono "165.058992" xsd:float
 property_value: Origin "F" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:127
-is_a: MOD:00498
-is_a: MOD:01066
+is_a: MOD:00498 ! fluorinated residue
+is_a: MOD:01066 ! halogenated phenylalanine
 
 [Term]
 id: MOD:01228
@@ -22258,8 +22257,8 @@ property_value: MassMono "288.959976" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:129
-is_a: MOD:00500
-is_a: MOD:00998
+is_a: MOD:00500 ! monoiodinated residue
+is_a: MOD:00998 ! iodinated tyrosine
 
 [Term]
 id: MOD:01229
@@ -22277,8 +22276,8 @@ property_value: MassMono "262.955560" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:129
-is_a: MOD:00500
-is_a: MOD:01049
+is_a: MOD:00500 ! monoiodinated residue
+is_a: MOD:01049 ! halogenated histidine
 
 [Term]
 id: MOD:01230
@@ -22295,7 +22294,7 @@ property_value: MassMono "233.116427" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:365
-is_a: MOD:00790
+is_a: MOD:00790 ! Bruker Daltonics SERVA-ICPL(TM) quantification chemistry, light form
 
 [Term]
 id: MOD:01231
@@ -22313,8 +22312,8 @@ property_value: MassMono "187.131242" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:59
-relationship: derives_from MOD:01398
-is_a: MOD:01428
+relationship: derives_from MOD:01398 ! N6-propanoyl-L-lysine
+is_a: MOD:01428 ! (13)C isotope tagged reagent
 
 [Term]
 id: MOD:01232
@@ -22332,8 +22331,8 @@ property_value: MassMono "184.121178" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:58
-relationship: derives_from MOD:01398
-is_a: MOD:01426
+relationship: derives_from MOD:01398 ! N6-propanoyl-L-lysine
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
 
 [Term]
 id: MOD:01233
@@ -22351,8 +22350,8 @@ property_value: MassMono "173.124358" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:56
-relationship: derives_from MOD:00064
-is_a: MOD:00449
+relationship: derives_from MOD:00064 ! N6-acetyl-L-lysine
+is_a: MOD:00449 ! acetate labeling reagent (N-term) (heavy form, +3amu)
 
 [Term]
 id: MOD:01234
@@ -22370,8 +22369,8 @@ property_value: MassMono "89.036275" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:258
-is_a: MOD:00581
-is_a: MOD:00916
+is_a: MOD:00581 ! (18)O monosubstituted residue
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:01235
@@ -22389,8 +22388,8 @@ property_value: MassMono "103.051925" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:258
-is_a: MOD:00581
-is_a: MOD:00917
+is_a: MOD:00581 ! (18)O monosubstituted residue
+is_a: MOD:00917 ! modified L-threonine residue
 
 [Term]
 id: MOD:01236
@@ -22408,8 +22407,8 @@ property_value: MassMono "165.067575" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:258
-is_a: MOD:00581
-is_a: MOD:00919
+is_a: MOD:00581 ! (18)O monosubstituted residue
+is_a: MOD:00919 ! modified L-tyrosine residue
 
 [Term]
 id: MOD:01237
@@ -22427,7 +22426,7 @@ property_value: MassMono "259.124215" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:53
-is_a: MOD:00446
+is_a: MOD:00446 ! 4-hydroxynonenal adduct
 
 [Term]
 id: MOD:01238
@@ -22445,7 +22444,7 @@ property_value: MassMono "284.209993" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:53
-is_a: MOD:00446
+is_a: MOD:00446 ! 4-hydroxynonenal adduct
 
 [Term]
 id: MOD:01239
@@ -22463,7 +22462,7 @@ property_value: MassMono "293.173942" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:53
-is_a: MOD:00446
+is_a: MOD:00446 ! 4-hydroxynonenal adduct
 
 [Term]
 id: MOD:01240
@@ -22480,10 +22479,10 @@ property_value: MassMono "511.323065" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:535
-is_a: MOD:02047
-is_a: MOD:02051
-is_a: MOD:01875
-relationship: derives_from MOD:01148
+is_a: MOD:02047 ! crosslinked glycine residue
+is_a: MOD:02051 ! crosslinked L-lysine residue
+is_a: MOD:01875 ! N6-acylated L-lysine
+relationship: derives_from MOD:01148 ! ubiquitinylated lysine
 
 [Term]
 id: MOD:01241
@@ -22501,9 +22500,9 @@ property_value: MassMono "132.061423" xsd:float
 property_value: Origin "D" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:298
-is_a: MOD:00617
-is_a: MOD:00904
-relationship: derives_from MOD:01181
+is_a: MOD:00617 ! 3x(2)H residue methyl ester
+is_a: MOD:00904 ! modified L-aspartic acid residue
+relationship: derives_from MOD:01181 ! L-aspartic acid 4-methyl ester
 
 [Term]
 id: MOD:01242
@@ -22521,9 +22520,9 @@ property_value: MassMono "146.077073" xsd:float
 property_value: Origin "E" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:298
-is_a: MOD:00617
-is_a: MOD:00906
-relationship: derives_from MOD:00081
+is_a: MOD:00617 ! 3x(2)H residue methyl ester
+is_a: MOD:00906 ! modified L-glutamic acid residue
+relationship: derives_from MOD:00081 ! L-glutamic acid 5-methyl ester (Glu)
 
 [Term]
 id: MOD:01243
@@ -22537,7 +22536,7 @@ property_value: DiffMono "37.955882" xsd:float
 property_value: Origin "X" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: Unimod:530
-is_a: MOD:01072
+is_a: MOD:01072 ! monopotassium salt
 
 [Term]
 id: MOD:01244
@@ -22553,8 +22552,8 @@ property_value: MassAvg "167.21" xsd:float
 property_value: MassMono "166.998475" xsd:float
 property_value: Origin "E" xsd:string
 xref: Unimod:530
-is_a: MOD:00906
-is_a: MOD:01072
+is_a: MOD:00906 ! modified L-glutamic acid residue
+is_a: MOD:01072 ! monopotassium salt
 
 [Term]
 id: MOD:01245
@@ -22570,8 +22569,8 @@ property_value: MassAvg "153.18" xsd:float
 property_value: MassMono "152.982825" xsd:float
 property_value: Origin "D" xsd:string
 xref: Unimod:530
-is_a: MOD:00904
-is_a: MOD:01072
+is_a: MOD:00904 ! modified L-aspartic acid residue
+is_a: MOD:01072 ! monopotassium salt
 
 [Term]
 id: MOD:01246
@@ -22625,8 +22624,8 @@ property_value: MassMono "485.083545" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:292
-is_a: MOD:00611
-is_a: MOD:00919
+is_a: MOD:00611 ! iodouridine monophosphate derivatized residue
+is_a: MOD:00919 ! modified L-tyrosine residue
 
 [Term]
 id: MOD:01249
@@ -22644,8 +22643,8 @@ property_value: MassMono "508.099530" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:292
-is_a: MOD:00611
-is_a: MOD:00918
+is_a: MOD:00611 ! iodouridine monophosphate derivatized residue
+is_a: MOD:00918 ! modified L-tryptophan residue
 
 [Term]
 id: MOD:01250
@@ -22663,8 +22662,8 @@ property_value: MassMono "469.088630" xsd:float
 property_value: Origin "F" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:292
-is_a: MOD:00611
-is_a: MOD:00914
+is_a: MOD:00611 ! iodouridine monophosphate derivatized residue
+is_a: MOD:00914 ! modified L-phenylalanine residue
 
 [Term]
 id: MOD:01251
@@ -22681,8 +22680,8 @@ property_value: MassMono "273.114712" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:293
-is_a: MOD:00612
-is_a: MOD:01875
+is_a: MOD:00612 ! 3-(carboxamidomethylthio)propanoylated residue
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01252
@@ -22717,8 +22716,8 @@ property_value: MassMono "182.105528" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:319
-is_a: MOD:00630
-is_a: MOD:00912
+is_a: MOD:00630 ! C3-H2-O adduct (+54 amu) of malondialdehyde with lysine or methylglyoxal with arginine.
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:01254
@@ -22737,9 +22736,9 @@ property_value: MassMono "160.151370" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:199
-is_a: MOD:00552
-is_a: MOD:00912
-relationship: derives_from MOD:00084
+is_a: MOD:00552 ! 4x(2)H labeled dimethylated residue
+is_a: MOD:00912 ! modified L-lysine residue
+relationship: derives_from MOD:00084 ! N6,N6-dimethyl-L-lysine
 
 [Term]
 id: MOD:01255
@@ -22757,8 +22756,8 @@ property_value: MassMono "163.012556" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:200
-is_a: MOD:00553
-is_a: MOD:00916
+is_a: MOD:00553 ! 1,2-ethanedithiol modified residue
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:01256
@@ -22776,8 +22775,8 @@ property_value: MassMono "177.028206" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:200
-is_a: MOD:00553
-is_a: MOD:00917
+is_a: MOD:00553 ! 1,2-ethanedithiol modified residue
+is_a: MOD:00917 ! modified L-threonine residue
 
 [Term]
 id: MOD:01257
@@ -22794,7 +22793,7 @@ property_value: MassMono "298.142976" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:194
-is_a: MOD:00547
+is_a: MOD:00547 ! 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate
 
 [Term]
 id: MOD:01258
@@ -22811,8 +22810,8 @@ property_value: MassMono "214.041213" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:314
-is_a: MOD:00625
-is_a: MOD:00905
+is_a: MOD:00625 ! N-methylmaleimide derivatized residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:01259
@@ -22829,8 +22828,8 @@ property_value: MassMono "239.126991" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:314
-is_a: MOD:00625
-is_a: MOD:00912
+is_a: MOD:00625 ! N-methylmaleimide derivatized residue
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:01260
@@ -23051,8 +23050,8 @@ property_value: MassMono "353.188546" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:89
-is_a: MOD:00467
-is_a: MOD:01875
+is_a: MOD:00467 ! iminobiotinyl modified residue
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01273
@@ -23069,8 +23068,8 @@ property_value: MassMono "270.067428" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:276
-is_a: MOD:00596
-is_a: MOD:00916
+is_a: MOD:00596 ! 4-(2-aminoethyl)benzenesulfonyl fluoride derivatized residue
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:01274
@@ -23087,8 +23086,8 @@ property_value: MassMono "320.094311" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:276
-is_a: MOD:00596
-is_a: MOD:00909
+is_a: MOD:00596 ! 4-(2-aminoethyl)benzenesulfonyl fluoride derivatized residue
+is_a: MOD:00909 ! modified L-histidine residue
 
 [Term]
 id: MOD:01275
@@ -23105,8 +23104,8 @@ property_value: MassMono "311.130363" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:276
-is_a: MOD:00596
-is_a: MOD:00912
+is_a: MOD:00596 ! 4-(2-aminoethyl)benzenesulfonyl fluoride derivatized residue
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:01276
@@ -23123,8 +23122,8 @@ property_value: MassMono "346.098728" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:276
-is_a: MOD:00596
-is_a: MOD:00919
+is_a: MOD:00596 ! 4-(2-aminoethyl)benzenesulfonyl fluoride derivatized residue
+is_a: MOD:00919 ! modified L-tyrosine residue
 
 [Term]
 id: MOD:01277
@@ -23141,8 +23140,8 @@ property_value: MassMono "173.051050" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:253
-is_a: MOD:00576
-is_a: MOD:00905
+is_a: MOD:00576 ! crotonylated residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:01278
@@ -23159,8 +23158,8 @@ property_value: MassMono "198.136828" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:253
-is_a: MOD:00576
-is_a: MOD:00912
+is_a: MOD:00576 ! crotonylated residue
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:01279
@@ -23177,8 +23176,8 @@ property_value: MassMono "207.100777" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:253
-is_a: MOD:00576
-is_a: MOD:00909
+is_a: MOD:00576 ! crotonylated residue
+is_a: MOD:00909 ! modified L-histidine residue
 
 [Term]
 id: MOD:01280
@@ -23195,8 +23194,8 @@ property_value: MassMono "591.221897" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:118
-is_a: MOD:00490
-is_a: MOD:00917
+is_a: MOD:00490 ! EDT-iodo-PEO-biotin
+is_a: MOD:00917 ! modified L-threonine residue
 
 [Term]
 id: MOD:01281
@@ -23213,8 +23212,8 @@ property_value: MassMono "577.206247" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:118
-is_a: MOD:00490
-is_a: MOD:00916
+is_a: MOD:00490 ! EDT-iodo-PEO-biotin
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:01282
@@ -23282,8 +23281,8 @@ property_value: MassMono "120.101228" xsd:float
 property_value: Origin "L" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:695
-is_a: MOD:00911
-is_a: MOD:01370
+is_a: MOD:00911 ! modified L-leucine residue
+is_a: MOD:01370 ! 6x(13)C,1x(15)N labeled residue
 
 [Term]
 id: MOD:01286
@@ -23300,8 +23299,8 @@ property_value: MassMono "120.101228" xsd:float
 property_value: Origin "I" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:695
-is_a: MOD:00910
-is_a: MOD:01370
+is_a: MOD:00910 ! modified L-isoleucine residue
+is_a: MOD:01370 ! 6x(13)C,1x(15)N labeled residue
 
 [Term]
 id: MOD:01287
@@ -23318,8 +23317,8 @@ property_value: MassMono "239.136556" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:364
-is_a: MOD:00789
-is_a: MOD:00912
+is_a: MOD:00789 ! Bruker Daltonics SERVA-ICPL(TM) quantification chemistry, heavy form
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:01288
@@ -23423,8 +23422,8 @@ property_value: MassMono "117.031189" xsd:float
 property_value: Origin "N" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:366
-is_a: MOD:00852
-relationship: derives_from MOD:00684
+is_a: MOD:00852 ! 1x(18)O labeled deamidated residue
+relationship: derives_from MOD:00684 ! deamidated L-asparagine
 
 [Term]
 id: MOD:01294
@@ -23457,8 +23456,8 @@ property_value: MassMono "137.008887" xsd:float
 property_value: Origin "D" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:30
-is_a: MOD:00423
-is_a: MOD:00904
+is_a: MOD:00423 ! monosodium salt
+is_a: MOD:00904 ! modified L-aspartic acid residue
 
 [Term]
 id: MOD:01296
@@ -23478,8 +23477,8 @@ property_value: MassMono "151.024537" xsd:float
 property_value: Origin "E" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:30
-is_a: MOD:00423
-is_a: MOD:00906
+is_a: MOD:00423 ! monosodium salt
+is_a: MOD:00906 ! modified L-glutamic acid residue
 
 [Term]
 id: MOD:01297
@@ -23497,8 +23496,8 @@ property_value: MassMono "102.069538" xsd:float
 property_value: Origin "P" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:772
-is_a: MOD:00915
-is_a: MOD:01832
+is_a: MOD:00915 ! modified L-proline residue
+is_a: MOD:01832 ! 5x(13)C-labeled residue
 
 [Term]
 id: MOD:01298
@@ -23516,9 +23515,9 @@ property_value: MassMono "261.139865" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:335
-is_a: MOD:00642
-is_a: MOD:00905
-relationship: derives_from MOD:01237
+is_a: MOD:00642 ! reduced 4-hydroxynonenal adduct
+is_a: MOD:00905 ! modified L-cysteine residue
+relationship: derives_from MOD:01237 ! cysteine 4-hydroxynonenal adduct
 
 [Term]
 id: MOD:01299
@@ -23536,9 +23535,9 @@ property_value: MassMono "286.225643" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:335
-is_a: MOD:00642
-is_a: MOD:00912
-relationship: derives_from MOD:01238
+is_a: MOD:00642 ! reduced 4-hydroxynonenal adduct
+is_a: MOD:00912 ! modified L-lysine residue
+relationship: derives_from MOD:01238 ! lysine 4-hydroxynonenal adduct
 
 [Term]
 id: MOD:01300
@@ -23556,9 +23555,9 @@ property_value: MassMono "295.189592" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:335
-is_a: MOD:00642
-is_a: MOD:00909
-relationship: derives_from MOD:01239
+is_a: MOD:00642 ! reduced 4-hydroxynonenal adduct
+is_a: MOD:00909 ! modified L-histidine residue
+relationship: derives_from MOD:01239 ! histidine 4-hydroxynonenal adduct
 
 [Term]
 id: MOD:01301
@@ -23576,8 +23575,8 @@ property_value: MassMono "114.079313" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:337
-is_a: MOD:00643
-is_a: MOD:00917
+is_a: MOD:00643 ! methylamine Michael addition derivatized residue
+is_a: MOD:00917 ! modified L-threonine residue
 
 [Term]
 id: MOD:01302
@@ -23595,8 +23594,8 @@ property_value: MassMono "100.063663" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:337
-is_a: MOD:00643
-is_a: MOD:00916
+is_a: MOD:00643 ! methylamine Michael addition derivatized residue
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:01303
@@ -23614,8 +23613,8 @@ property_value: MassMono "275.111735" xsd:float
 property_value: Origin "N" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:454
-is_a: MOD:00160
-is_a: MOD:00876
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
+is_a: MOD:00876 ! hexosaminylated residue
 
 [Term]
 id: MOD:01304
@@ -23632,8 +23631,8 @@ property_value: MassMono "289.163771" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:454
-is_a: MOD:00876
-is_a: MOD:00912
+is_a: MOD:00876 ! hexosaminylated residue
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:01305
@@ -23651,8 +23650,8 @@ property_value: MassMono "347.148121" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:454
-is_a: MOD:00876
-is_a: MOD:00918
+is_a: MOD:00876 ! hexosaminylated residue
+is_a: MOD:00918 ! modified L-tryptophan residue
 
 [Term]
 id: MOD:01306
@@ -23670,8 +23669,8 @@ property_value: MassMono "262.116486" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:454
-is_a: MOD:00005
-is_a: MOD:00876
+is_a: MOD:00005 ! O-glycosyl-L-threonine
+is_a: MOD:00876 ! hexosaminylated residue
 
 [Term]
 id: MOD:01307
@@ -23688,8 +23687,8 @@ property_value: MassMono "612.174923" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:332
-is_a: MOD:00639
-is_a: MOD:00916
+is_a: MOD:00639 ! thiophosphate labeled with biotin-HPDP
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:01308
@@ -23706,8 +23705,8 @@ property_value: MassMono "626.190573" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:332
-is_a: MOD:00639
-is_a: MOD:00917
+is_a: MOD:00639 ! thiophosphate labeled with biotin-HPDP
+is_a: MOD:00917 ! modified L-threonine residue
 
 [Term]
 id: MOD:01309
@@ -23724,8 +23723,8 @@ property_value: MassMono "688.206223" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:332
-is_a: MOD:00639
-is_a: MOD:00919
+is_a: MOD:00639 ! thiophosphate labeled with biotin-HPDP
+is_a: MOD:00919 ! modified L-tyrosine residue
 
 [Term]
 id: MOD:01310
@@ -23742,8 +23741,8 @@ property_value: MassMono "187.168462" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:60
-is_a: MOD:00912
-is_a: MOD:01426
+is_a: MOD:00912 ! modified L-lysine residue
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
 
 [Term]
 id: MOD:01311
@@ -23760,8 +23759,8 @@ property_value: MassMono "190.187293" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:61
-is_a: MOD:00912
-is_a: MOD:01426
+is_a: MOD:00912 ! modified L-lysine residue
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
 
 [Term]
 id: MOD:01312
@@ -23779,8 +23778,8 @@ property_value: MassMono "193.206123" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:62
-is_a: MOD:00912
-is_a: MOD:01426
+is_a: MOD:00912 ! modified L-lysine residue
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
 
 [Term]
 id: MOD:01313
@@ -23797,8 +23796,8 @@ property_value: MassMono "196.224953" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:63
-is_a: MOD:00912
-is_a: MOD:01426
+is_a: MOD:00912 ! modified L-lysine residue
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
 
 [Term]
 id: MOD:01314
@@ -23815,9 +23814,9 @@ property_value: MassMono "228.111007" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:64
-relationship: derives_from MOD:01819
-is_a: MOD:00670
-is_a: MOD:01426
+relationship: derives_from MOD:01819 ! N6-succinyl-L-lysine
+is_a: MOD:00670 ! N-acylated residue
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
 
 [Term]
 id: MOD:01315
@@ -23834,9 +23833,9 @@ property_value: MassMono "232.136114" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:65
-relationship: derives_from MOD:01819
-is_a: MOD:00670
-is_a: MOD:01426
+relationship: derives_from MOD:01819 ! N6-succinyl-L-lysine
+is_a: MOD:00670 ! N-acylated residue
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
 
 [Term]
 id: MOD:01316
@@ -23853,9 +23852,9 @@ property_value: MassMono "232.124426" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:66
-relationship: derives_from MOD:01819
-is_a: MOD:00670
-is_a: MOD:01428
+relationship: derives_from MOD:01819 ! N6-succinyl-L-lysine
+is_a: MOD:00670 ! N-acylated residue
+is_a: MOD:01428 ! (13)C isotope tagged reagent
 
 [Term]
 id: MOD:01317
@@ -23872,8 +23871,8 @@ property_value: MassMono "188.098334" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:178
-is_a: MOD:00535
-is_a: MOD:00917
+is_a: MOD:00535 ! phosphorylation to amine thiol
+is_a: MOD:00917 ! modified L-threonine residue
 
 [Term]
 id: MOD:01318
@@ -23890,8 +23889,8 @@ property_value: MassMono "174.082684" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:178
-is_a: MOD:00535
-is_a: MOD:00916
+is_a: MOD:00535 ! phosphorylation to amine thiol
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:01319
@@ -23909,8 +23908,8 @@ property_value: MassMono "355.225977" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:176
-is_a: MOD:00534
-is_a: MOD:00909
+is_a: MOD:00534 ! Michael addition of BHT quinone methide to cysteine and lysine
+is_a: MOD:00909 ! modified L-histidine residue
 
 [Term]
 id: MOD:01320
@@ -23928,8 +23927,8 @@ property_value: MassMono "346.262028" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:176
-is_a: MOD:00534
-is_a: MOD:00912
+is_a: MOD:00534 ! Michael addition of BHT quinone methide to cysteine and lysine
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:01321
@@ -23947,8 +23946,8 @@ property_value: MassMono "321.176250" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:176
-is_a: MOD:00534
-is_a: MOD:00905
+is_a: MOD:00534 ! Michael addition of BHT quinone methide to cysteine and lysine
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:01322
@@ -24033,8 +24032,8 @@ property_value: MassMono "172.093522" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:184
-is_a: MOD:00540
-is_a: MOD:00919
+is_a: MOD:00540 ! 9x(13)C labeled residue
+is_a: MOD:00919 ! modified L-tyrosine residue
 
 [Term]
 id: MOD:01327
@@ -24051,8 +24050,8 @@ property_value: MassMono "156.098607" xsd:float
 property_value: Origin "F" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:184
-is_a: MOD:00540
-is_a: MOD:00914
+is_a: MOD:00540 ! 9x(13)C labeled residue
+is_a: MOD:00914 ! modified L-phenylalanine residue
 
 [Term]
 id: MOD:01328
@@ -24070,8 +24069,8 @@ property_value: MassMono "244.084792" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:6
-is_a: MOD:00399
-is_a: MOD:00918
+is_a: MOD:00399 ! iodoacetic acid derivatized residue
+is_a: MOD:00918 ! modified L-tryptophan residue
 
 [Term]
 id: MOD:01329
@@ -24122,7 +24121,7 @@ property_value: MassMono "162.121240" xsd:float
 property_value: Origin "R" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:188
-is_a: MOD:00544
+is_a: MOD:00544 ! 6x(13)C labeled residue
 
 [Term]
 id: MOD:01332
@@ -24140,7 +24139,7 @@ property_value: MassMono "119.104193" xsd:float
 property_value: Origin "L" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:188
-is_a: MOD:00544
+is_a: MOD:00544 ! 6x(13)C labeled residue
 
 [Term]
 id: MOD:01333
@@ -24158,7 +24157,7 @@ property_value: MassMono "119.104193" xsd:float
 property_value: Origin "I" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:188
-is_a: MOD:00544
+is_a: MOD:00544 ! 6x(13)C labeled residue
 
 [Term]
 id: MOD:01334
@@ -24177,7 +24176,7 @@ property_value: MassMono "134.115092" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:188
-is_a: MOD:00544
+is_a: MOD:00544 ! 6x(13)C labeled residue
 
 [Term]
 id: MOD:01335
@@ -24194,8 +24193,8 @@ property_value: MassMono "349.086177" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:464
-is_a: MOD:00880
-is_a: MOD:00912
+is_a: MOD:00880 ! 6x(13)C labeled 4-sulfophenyl isothiocyanate derivatized residue
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:01336
@@ -24229,8 +24228,8 @@ property_value: MassMono "129.042593" xsd:float
 property_value: Origin "N" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:528
-relationship: derives_from MOD:01181
-is_a: MOD:01369
+relationship: derives_from MOD:01181 ! L-aspartic acid 4-methyl ester
+is_a: MOD:01369 ! deamidated and methyl esterified residue
 
 [Term]
 id: MOD:01338
@@ -24248,8 +24247,8 @@ property_value: MassMono "156.126263" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: Unimod:280
-is_a: MOD:00912
-is_a: MOD:01339
+is_a: MOD:00912 ! modified L-lysine residue
+is_a: MOD:01339 ! ethylated residue
 
 [Term]
 id: MOD:01339
@@ -24265,7 +24264,7 @@ property_value: DiffMono "28.031300" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:280
-is_a: MOD:00001
+is_a: MOD:00001 ! alkylated residue
 
 [Term]
 id: MOD:01340
@@ -24282,8 +24281,8 @@ property_value: MassMono "476.335378" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:91
-is_a: MOD:00469
-is_a: MOD:00912
+is_a: MOD:00469 ! ESP-Tag heavy d10
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:01341
@@ -24300,8 +24299,8 @@ property_value: MassMono "466.272610" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:90
-is_a: MOD:00468
-is_a: MOD:00912
+is_a: MOD:00468 ! ESP-Tag light d0
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:01342
@@ -24373,8 +24372,8 @@ property_value: MassMono "99.032028" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:401
-is_a: MOD:00917
-is_a: MOD:01888
+is_a: MOD:00917 ! modified L-threonine residue
+is_a: MOD:01888 ! didehydrogenated residue
 
 [Term]
 id: MOD:01346
@@ -24391,8 +24390,8 @@ property_value: MassMono "276.095751" xsd:float
 property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:41
-is_a: MOD:00160
-is_a: MOD:00434
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
+is_a: MOD:00434 ! hexosylated residue
 
 [Term]
 id: MOD:01347
@@ -24409,8 +24408,8 @@ property_value: MassMono "290.147786" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:41
-is_a: MOD:00767
-is_a: MOD:00912
+is_a: MOD:00767 ! glycated residue
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:01348
@@ -24427,8 +24426,8 @@ property_value: MassMono "263.100502" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:41
-is_a: MOD:00005
-is_a: MOD:00434
+is_a: MOD:00005 ! O-glycosyl-L-threonine
+is_a: MOD:00434 ! hexosylated residue
 
 [Term]
 id: MOD:01349
@@ -24446,8 +24445,8 @@ property_value: MassMono "246.067428" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:320
-is_a: MOD:00631
-is_a: MOD:00905
+is_a: MOD:00631 ! hydrolyzed N-ethylmaleimide adduct
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:01350
@@ -24465,7 +24464,7 @@ property_value: MassMono "271.153206" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:320
-is_a: MOD:00631
+is_a: MOD:00631 ! hydrolyzed N-ethylmaleimide adduct
 
 [Term]
 id: MOD:01351
@@ -24484,8 +24483,8 @@ property_value: MassMono "231.064391" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:354
-is_a: MOD:00461
-is_a: MOD:00918
+is_a: MOD:00461 ! nitrated residue
+is_a: MOD:00918 ! modified L-tryptophan residue
 
 [Term]
 id: MOD:01352
@@ -24506,8 +24505,8 @@ property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:354
 xref: uniprot.ptm:PTM-0213
-is_a: MOD:00461
-is_a: MOD:00919
+is_a: MOD:00461 ! nitrated residue
+is_a: MOD:00919 ! modified L-tyrosine residue
 
 [Term]
 id: MOD:01353
@@ -24524,8 +24523,8 @@ property_value: MassMono "169.121512" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:141
-is_a: MOD:00509
-is_a: MOD:00912
+is_a: MOD:00509 ! amidination of lysines or N-terminal amines with methyl acetimidate
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:01354
@@ -24542,8 +24541,8 @@ property_value: MassMono "771.278365" xsd:float
 property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:149
-is_a: MOD:00517
-is_a: MOD:00160
+is_a: MOD:00517 ! Hex1HexNAc1NeuAc1 glycosylated residue
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:01355
@@ -24560,8 +24559,8 @@ property_value: MassMono "758.283116" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:149
-is_a: MOD:00517
-is_a: MOD:00005
+is_a: MOD:00517 ! Hex1HexNAc1NeuAc1 glycosylated residue
+is_a: MOD:00005 ! O-glycosyl-L-threonine
 
 [Term]
 id: MOD:01356
@@ -24578,8 +24577,8 @@ property_value: MassMono "744.267466" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:149
-is_a: MOD:00517
-is_a: MOD:00916
+is_a: MOD:00517 ! Hex1HexNAc1NeuAc1 glycosylated residue
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:01357
@@ -24596,9 +24595,9 @@ property_value: MassMono "162.158080" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:510
-is_a: MOD:00912
-is_a: MOD:00927
-relationship: derives_from MOD:00084
+is_a: MOD:00912 ! modified L-lysine residue
+is_a: MOD:00927 ! 2x(13)C,4x(2)H labeled dimethylated residue
+relationship: derives_from MOD:00084 ! N6,N6-dimethyl-L-lysine
 
 [Term]
 id: MOD:01358
@@ -24613,7 +24612,7 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:687
-is_a: MOD:01426
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
 
 [Term]
 id: MOD:01359
@@ -24630,8 +24629,8 @@ property_value: MassMono "237.141534" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:687
-is_a: MOD:00912
-is_a: MOD:01426
+is_a: MOD:00912 ! modified L-lysine residue
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
 
 [Term]
 id: MOD:01360
@@ -24649,8 +24648,8 @@ property_value: MassMono "343.066048" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:261
-is_a: MOD:00584
-is_a: MOD:00912
+is_a: MOD:00584 ! 4-sulfophenyl isothiocyanate derivatized residue
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:01361
@@ -24667,8 +24666,8 @@ property_value: MassMono "196.991165" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:260
-is_a: MOD:00583
-is_a: MOD:00917
+is_a: MOD:00583 ! thiophosphorylated residue
+is_a: MOD:00917 ! modified L-threonine residue
 
 [Term]
 id: MOD:01362
@@ -24685,8 +24684,8 @@ property_value: MassMono "182.975515" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:260
-is_a: MOD:00583
-is_a: MOD:00916
+is_a: MOD:00583 ! thiophosphorylated residue
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:01363
@@ -24703,8 +24702,8 @@ property_value: MassMono "259.006815" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:260
-is_a: MOD:00583
-is_a: MOD:00919
+is_a: MOD:00583 ! thiophosphorylated residue
+is_a: MOD:00919 ! modified L-tyrosine residue
 
 [Term]
 id: MOD:01364
@@ -24721,8 +24720,8 @@ property_value: MassMono "508.105270" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:478
-is_a: MOD:00626
-is_a: MOD:00916
+is_a: MOD:00626 ! fluorescein-5-thiosemicarbazide modified residue
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:01365
@@ -24739,8 +24738,8 @@ property_value: MassMono "524.082426" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:478
-is_a: MOD:00626
-is_a: MOD:00905
+is_a: MOD:00626 ! fluorescein-5-thiosemicarbazide modified residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:01366
@@ -24757,8 +24756,8 @@ property_value: MassMono "549.168205" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:478
-is_a: MOD:00626
-is_a: MOD:00912
+is_a: MOD:00626 ! fluorescein-5-thiosemicarbazide modified residue
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:01367
@@ -24775,8 +24774,8 @@ property_value: MassMono "518.126005" xsd:float
 property_value: Origin "P" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:478
-is_a: MOD:00626
-is_a: MOD:00915
+is_a: MOD:00626 ! fluorescein-5-thiosemicarbazide modified residue
+is_a: MOD:00915 ! modified L-proline residue
 
 [Term]
 id: MOD:01368
@@ -24793,8 +24792,8 @@ property_value: MassMono "577.174353" xsd:float
 property_value: Origin "R" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:478
-is_a: MOD:00626
-is_a: MOD:00902
+is_a: MOD:00626 ! fluorescein-5-thiosemicarbazide modified residue
+is_a: MOD:00902 ! modified L-arginine residue
 
 [Term]
 id: MOD:01369
@@ -24808,8 +24807,8 @@ property_value: DiffFormula "C 1 H 1 N -1 O 1" xsd:string
 property_value: DiffMono "14.999666" xsd:float
 property_value: Origin "X" xsd:string
 xref: Unimod:528
-is_a: MOD:00393
-relationship: contains MOD:00400
+is_a: MOD:00393 ! O-methylated residue
+relationship: contains MOD:00400 ! deamidated residue
 
 [Term]
 id: MOD:01370
@@ -24823,8 +24822,8 @@ property_value: DiffMono "7.017164" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:695
-is_a: MOD:00842
-is_a: MOD:00843
+is_a: MOD:00842 ! (13)C labeled residue
+is_a: MOD:00843 ! (15)N labeled residue
 
 [Term]
 id: MOD:01371
@@ -24857,7 +24856,7 @@ property_value: MassMono "129.078979" xsd:float
 property_value: Origin "L" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0665
-is_a: MOD:01411
+is_a: MOD:01411 ! monohydroxylated leucine
 
 [Term]
 id: MOD:01373
@@ -24877,7 +24876,7 @@ property_value: MassMono "129.078979" xsd:float
 property_value: Origin "L" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: uniprot.ptm:PTM-0491
-is_a: MOD:01411
+is_a: MOD:01411 ! monohydroxylated leucine
 
 [Term]
 id: MOD:01374
@@ -24895,8 +24894,8 @@ property_value: MassMono "127.063329" xsd:float
 property_value: Origin "L" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: uniprot.ptm:PTM-0492
-is_a: MOD:00679
-is_a: MOD:00911
+is_a: MOD:00679 ! carbon oxygenated residue
+is_a: MOD:00911 ! modified L-leucine residue
 
 [Term]
 id: MOD:01375
@@ -24916,7 +24915,7 @@ property_value: MassMono "145.073893" xsd:float
 property_value: Origin "L" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0340
-is_a: MOD:01412
+is_a: MOD:01412 ! dihydroxylated leucine
 
 [Term]
 id: MOD:01376
@@ -24936,7 +24935,7 @@ property_value: MassMono "145.073893" xsd:float
 property_value: Origin "I" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0343
-is_a: MOD:01416
+is_a: MOD:01416 ! dihydroxylated isoleucine
 
 [Term]
 id: MOD:01377
@@ -24957,7 +24956,7 @@ property_value: MassMono "129.078979" xsd:float
 property_value: Origin "I" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0337
-is_a: MOD:01415
+is_a: MOD:01415 ! monohydroxylated isoleucine
 
 [Term]
 id: MOD:01378
@@ -24977,7 +24976,7 @@ property_value: MassMono "145.073893" xsd:float
 property_value: Origin "I" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0336
-is_a: MOD:01416
+is_a: MOD:01416 ! dihydroxylated isoleucine
 
 [Term]
 id: MOD:01379
@@ -24995,7 +24994,7 @@ property_value: MassMono "264.056863" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0304
-is_a: MOD:00918
+is_a: MOD:00918 ! modified L-tryptophan residue
 
 [Term]
 id: MOD:01380
@@ -25015,8 +25014,8 @@ property_value: MassMono "319.062677" xsd:float
 property_value: Origin "C, W" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0338
-is_a: MOD:00687
-is_a: MOD:02057
+is_a: MOD:00687 ! thioether crosslinked residues
+is_a: MOD:02057 ! crosslinked L-tryptophan residue
 
 [Term]
 id: MOD:01381
@@ -25038,8 +25037,8 @@ property_value: MassMono "323.246044" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0493
-is_a: MOD:02003
-is_a: MOD:01768
+is_a: MOD:02003 ! O3-acylated L-serine
+is_a: MOD:01768 ! O-palmitoleylated residue
 
 [Term]
 id: MOD:01382
@@ -25065,8 +25064,8 @@ property_value: Origin "M" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0503
-is_a: MOD:01463
-is_a: MOD:01698
+is_a: MOD:01463 ! N-methylated methionine
+is_a: MOD:01698 ! alpha-amino trimethylated protonated-residue
 
 [Term]
 id: MOD:01383
@@ -25088,8 +25087,8 @@ property_value: MassMono "219.997634" xsd:float
 property_value: Origin "C, C" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: uniprot.ptm:PTM-0324
-is_a: MOD:02044
-is_a: MOD:00689
+is_a: MOD:02044 ! crosslinked L-cysteine residue
+is_a: MOD:00689 ! disulfide crosslinked residues
 
 [Term]
 id: MOD:01384
@@ -25109,7 +25108,7 @@ property_value: MassMono "101.011293" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: uniprot.ptm:PTM-0321
-is_a: MOD:00916
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:01385
@@ -25125,6 +25124,9 @@ synonym: "beta-phenylserine" EXACT RESID-alternate []
 synonym: "hydroxylationf" EXACT OMSSA-label []
 synonym: "L-threo-3-phenylserine" EXACT RESID-alternate []
 synonym: "MOD_RES 3-hydroxyphenylalanine" EXACT UniProt-feature []
+synonym: "L-m-Tyrosine" EXACT PSI-MOD-label []
+synonym: "(S)-2-amino-3-(3-hydroxyphenyl)propanoic acid" EXACT PSI-MOD-label []
+synonym: "Meta-Tyrosine" EXACT PSI-MOD-label []
 property_value: DiffAvg "16.00" xsd:float
 property_value: DiffFormula "C 0 H 0 N 0 O 1" xsd:string
 property_value: DiffMono "15.994915" xsd:float
@@ -25134,8 +25136,9 @@ property_value: MassMono "163.063329" xsd:float
 property_value: Origin "F" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0346
-is_a: MOD:00677
-is_a: MOD:00914
+is_a: MOD:00677 ! hydroxylated residue
+is_a: MOD:00914 ! modified L-phenylalanine residue
+is_a: MOD:02116 ! monohydroxylated phenylalanine
 
 [Term]
 id: MOD:01386
@@ -25155,8 +25158,8 @@ property_value: MassMono "115.063329" xsd:float
 property_value: Origin "V" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0347
-is_a: MOD:00677
-is_a: MOD:00920
+is_a: MOD:00677 ! hydroxylated residue
+is_a: MOD:00920 ! modified L-valine residue
 
 [Term]
 id: MOD:01387
@@ -25177,7 +25180,7 @@ property_value: MassMono "115.063329" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0356
-is_a: MOD:01803
+is_a: MOD:01803 ! O-methylated threonine
 
 [Term]
 id: MOD:01388
@@ -25207,8 +25210,8 @@ property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0354
-is_a: MOD:00917
-is_a: MOD:00960
+is_a: MOD:00917 ! modified L-threonine residue
+is_a: MOD:00960 ! decarboxylated residue
 
 [Term]
 id: MOD:01389
@@ -25228,9 +25231,9 @@ property_value: MassMono "196.067034" xsd:float
 property_value: Origin "C, I" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0361
-is_a: MOD:02049
-is_a: MOD:01420
-is_a: MOD:02082
+is_a: MOD:02049 ! crosslinked L-isoleucine residue
+is_a: MOD:01420 ! thiazole/thiazoline ring crosslinked residues
+is_a: MOD:02082 ! didehydrogenated and dehydrated residue
 
 [Term]
 id: MOD:01390
@@ -25250,9 +25253,9 @@ property_value: MassMono "182.051384" xsd:float
 property_value: Origin "C, V" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0365
-is_a: MOD:02059
-is_a: MOD:01420
-is_a: MOD:02082
+is_a: MOD:02059 ! crosslinked L-valine residue
+is_a: MOD:01420 ! thiazole/thiazoline ring crosslinked residues
+is_a: MOD:02082 ! didehydrogenated and dehydrated residue
 
 [Term]
 id: MOD:01391
@@ -25272,8 +25275,8 @@ property_value: MassMono "226.077599" xsd:float
 property_value: Origin "C, V" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0373
-is_a: MOD:02059
-is_a: MOD:01420
+is_a: MOD:02059 ! crosslinked L-valine residue
+is_a: MOD:01420 ! thiazole/thiazoline ring crosslinked residues
 
 [Term]
 id: MOD:01392
@@ -25293,9 +25296,9 @@ property_value: MassMono "211.041548" xsd:float
 property_value: Origin "C, N" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0352
-is_a: MOD:02042
-is_a: MOD:01420
-relationship: derives_from MOD:00656
+is_a: MOD:02042 ! crosslinked L-asparagine residue
+is_a: MOD:01420 ! thiazole/thiazoline ring crosslinked residues
+relationship: derives_from MOD:00656 ! C-methylated residue
 
 [Term]
 id: MOD:01393
@@ -25313,9 +25316,9 @@ property_value: MassMono "207.022823" xsd:float
 property_value: Origin "C, S, S" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0358
-is_a: MOD:02044
-is_a: MOD:02055
-is_a: MOD:01425
+is_a: MOD:02044 ! crosslinked L-cysteine residue
+is_a: MOD:02055 ! crosslinked L-serine residue
+is_a: MOD:01425 ! pyridinyl ring crosslinked residues
 
 [Term]
 id: MOD:01394
@@ -25336,9 +25339,9 @@ property_value: Origin "C, S, S" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0348
-is_a: MOD:02044
-is_a: MOD:02055
-is_a: MOD:01425
+is_a: MOD:02044 ! crosslinked L-cysteine residue
+is_a: MOD:02055 ! crosslinked L-serine residue
+is_a: MOD:01425 ! pyridinyl ring crosslinked residues
 
 [Term]
 id: MOD:01395
@@ -25357,9 +25360,9 @@ property_value: MassMono "430.197811" xsd:float
 property_value: Origin "I, T" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:02049
-is_a: MOD:02056
-is_a: MOD:01424
+is_a: MOD:02049 ! crosslinked L-isoleucine residue
+is_a: MOD:02056 ! crosslinked L-threonine residue
+is_a: MOD:01424 ! quinaldate modified residue
 
 [Term]
 id: MOD:01396
@@ -25380,9 +25383,9 @@ property_value: MassAvg "127.14" xsd:float
 property_value: MassMono "127.063329" xsd:float
 property_value: Origin "P" xsd:string
 property_value: Source "artifactual" xsd:string
-is_a: MOD:00915
-relationship: has_functional_parent MOD:01024
-relationship: has_functional_parent MOD:01417
+is_a: MOD:00915 ! modified L-proline residue
+relationship: has_functional_parent MOD:01024 ! monohydroxylated proline
+relationship: has_functional_parent MOD:01417 ! monomethylated proline
 
 [Term]
 id: MOD:01397
@@ -25402,9 +25405,9 @@ property_value: MassMono "168.053492" xsd:float
 property_value: Origin "S, T" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0386
-is_a: MOD:02055
-is_a: MOD:01422
-is_a: MOD:02082
+is_a: MOD:02055 ! crosslinked L-serine residue
+is_a: MOD:01422 ! oxazole/oxazoline ring crosslinked residues (Thr)
+is_a: MOD:02082 ! didehydrogenated and dehydrated residue
 
 [Term]
 id: MOD:01398
@@ -25431,9 +25434,9 @@ property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:58
 xref: uniprot.ptm:PTM-0642
-is_a: MOD:01155
-is_a: MOD:01875
-is_a: MOD:01894
+is_a: MOD:01155 ! lipoconjugated residue
+is_a: MOD:01875 ! N6-acylated L-lysine
+is_a: MOD:01894 ! propanoylated residue
 
 [Term]
 id: MOD:01399
@@ -25456,8 +25459,8 @@ property_value: MassMono "669.156072" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: uniprot.ptm:PTM-0355
-is_a: MOD:00752
-is_a: MOD:00912
+is_a: MOD:00752 ! adenosine diphosphoribosyl (ADP-ribosyl) modified residue
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:01400
@@ -25469,8 +25472,8 @@ synonym: "poly[2'-adenosine 5'-(trihydrogen diphosphate) 5'->5'-ester with 1alph
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
-is_a: MOD:02087
-is_a: MOD:00912
+is_a: MOD:02087 ! adenosine diphosphoribosyl (ADP-ribosyl) modified residue
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:01401
@@ -25492,7 +25495,7 @@ property_value: MassMono "130.037842" xsd:float
 property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0370
-is_a: MOD:01688
+is_a: MOD:01688 ! 3-hydroxy-L-asparagine
 
 [Term]
 id: MOD:01402
@@ -25512,7 +25515,7 @@ property_value: MassMono "129.042593" xsd:float
 property_value: Origin "P" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0368
-is_a: MOD:00866
+is_a: MOD:00866 ! dihydroxylated proline
 
 [Term]
 id: MOD:01403
@@ -25532,7 +25535,7 @@ property_value: MassMono "161.068808" xsd:float
 property_value: Origin "L" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0372
-is_a: MOD:01413
+is_a: MOD:01413 ! trihydroxylated leucine
 
 [Term]
 id: MOD:01404
@@ -25552,9 +25555,9 @@ property_value: MassMono "197.025897" xsd:float
 property_value: Origin "C, N" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0359
-is_a: MOD:02042
-is_a: MOD:01420
-is_a: MOD:02082
+is_a: MOD:02042 ! crosslinked L-asparagine residue
+is_a: MOD:01420 ! thiazole/thiazoline ring crosslinked residues
+is_a: MOD:02082 ! didehydrogenated and dehydrated residue
 
 [Term]
 id: MOD:01405
@@ -25572,9 +25575,9 @@ property_value: MassAvg "180.22" xsd:float
 property_value: MassMono "180.035734" xsd:float
 property_value: Origin "C, P" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:02054
-is_a: MOD:01420
-is_a: MOD:02082
+is_a: MOD:02054 ! crosslinked L-proline residue
+is_a: MOD:01420 ! thiazole/thiazoline ring crosslinked residues
+is_a: MOD:02082 ! didehydrogenated and dehydrated residue
 
 [Term]
 id: MOD:01406
@@ -25594,9 +25597,9 @@ property_value: MassMono "184.030649" xsd:float
 property_value: Origin "C, T" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0364
-is_a: MOD:02056
-is_a: MOD:01420
-is_a: MOD:02082
+is_a: MOD:02056 ! crosslinked L-threonine residue
+is_a: MOD:01420 ! thiazole/thiazoline ring crosslinked residues
+is_a: MOD:02082 ! didehydrogenated and dehydrated residue
 
 [Term]
 id: MOD:01407
@@ -25616,9 +25619,9 @@ property_value: MassMono "232.067034" xsd:float
 property_value: Origin "C, F" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0366
-is_a: MOD:02053
-is_a: MOD:01420
-is_a: MOD:00954
+is_a: MOD:02053 ! crosslinked L-phenylalanine residue
+is_a: MOD:01420 ! thiazole/thiazoline ring crosslinked residues
+is_a: MOD:00954 ! crosslinked residues with loss of water
 
 [Term]
 id: MOD:01408
@@ -25638,9 +25641,9 @@ property_value: MassMono "186.046299" xsd:float
 property_value: Origin "C, T" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0392
-is_a: MOD:02056
-is_a: MOD:01420
-is_a: MOD:00954
+is_a: MOD:02056 ! crosslinked L-threonine residue
+is_a: MOD:01420 ! thiazole/thiazoline ring crosslinked residues
+is_a: MOD:00954 ! crosslinked residues with loss of water
 
 [Term]
 id: MOD:01409
@@ -25651,7 +25654,7 @@ property_value: DiffAvg "48.00" xsd:float
 property_value: DiffFormula "C 0 H 0 N 0 O 3" xsd:string
 property_value: DiffMono "47.984744" xsd:float
 property_value: Origin "X" xsd:string
-is_a: MOD:00677
+is_a: MOD:00677 ! hydroxylated residue
 
 [Term]
 id: MOD:01410
@@ -25659,8 +25662,8 @@ name: hydroxylated leucine
 def: "A protein modification that effectively converts an L-leucine residue to an hydroxylated leucine." [PubMed:18688235]
 synonym: "HyLeu" EXACT PSI-MOD-label []
 property_value: Origin "L" xsd:string
-is_a: MOD:00677
-is_a: MOD:00911
+is_a: MOD:00677 ! hydroxylated residue
+is_a: MOD:00911 ! modified L-leucine residue
 
 [Term]
 id: MOD:01411
@@ -25675,8 +25678,8 @@ property_value: MassAvg "129.16" xsd:float
 property_value: MassMono "129.078979" xsd:float
 property_value: Origin "L" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00425
-is_a: MOD:01410
+is_a: MOD:00425 ! monohydroxylated residue
+is_a: MOD:01410 ! hydroxylated leucine
 
 [Term]
 id: MOD:01412
@@ -25691,8 +25694,8 @@ property_value: MassAvg "145.16" xsd:float
 property_value: MassMono "145.073893" xsd:float
 property_value: Origin "L" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00428
-is_a: MOD:01410
+is_a: MOD:00428 ! dihydroxylated residue
+is_a: MOD:01410 ! hydroxylated leucine
 
 [Term]
 id: MOD:01413
@@ -25707,8 +25710,8 @@ property_value: MassAvg "161.16" xsd:float
 property_value: MassMono "161.068808" xsd:float
 property_value: Origin "L" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:01409
-is_a: MOD:01410
+is_a: MOD:01409 ! trihydroxylated residue
+is_a: MOD:01410 ! hydroxylated leucine
 
 [Term]
 id: MOD:01414
@@ -25716,8 +25719,8 @@ name: hydroxylated isoleucine
 def: "A protein modification that effectively converts an L-isoleucine residue to an hydroxylated isoleucine." [PubMed:18688235]
 synonym: "HyIle" EXACT PSI-MOD-label []
 property_value: Origin "I" xsd:string
-is_a: MOD:00677
-is_a: MOD:00910
+is_a: MOD:00677 ! hydroxylated residue
+is_a: MOD:00910 ! modified L-isoleucine residue
 
 [Term]
 id: MOD:01415
@@ -25732,8 +25735,8 @@ property_value: MassAvg "129.16" xsd:float
 property_value: MassMono "129.078979" xsd:float
 property_value: Origin "I" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00425
-is_a: MOD:01414
+is_a: MOD:00425 ! monohydroxylated residue
+is_a: MOD:01414 ! hydroxylated isoleucine
 
 [Term]
 id: MOD:01416
@@ -25748,8 +25751,8 @@ property_value: MassAvg "145.16" xsd:float
 property_value: MassMono "145.073893" xsd:float
 property_value: Origin "I" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00428
-is_a: MOD:01414
+is_a: MOD:00428 ! dihydroxylated residue
+is_a: MOD:01414 ! hydroxylated isoleucine
 
 [Term]
 id: MOD:01417
@@ -25765,8 +25768,8 @@ property_value: MassAvg "112.15" xsd:float
 property_value: MassMono "112.076239" xsd:float
 property_value: Origin "P" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00599
-is_a: MOD:00712
+is_a: MOD:00599 ! monomethylated residue
+is_a: MOD:00712 ! methylated proline
 
 [Term]
 id: MOD:01418
@@ -25775,14 +25778,14 @@ def: "A protein modification that effectively converts an L-threonine residue to
 synonym: "MeThr" EXACT PSI-MOD-label []
 property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00427
-is_a: MOD:00917
+is_a: MOD:00427 ! methylated residue
+is_a: MOD:00917 ! modified L-threonine residue
 
 [Term]
 id: MOD:01419
 name: oxazole/oxazoline ring crosslinked residues
 def: "A protein modification that crosslinks two residues by condensation of a serine or threonine hydroxyl with the carbonyl of the preceding residue to form an oxazole or oxazoline ring, or by rearrangement and condensation of a cysteine with the carbonyl of the preceding residue to form a 1,3-oxazole-4-carbothionic acid." [PubMed:18688235]
-is_a: MOD:00690
+is_a: MOD:00690 ! oxazole/thiazole ring crosslinked residues
 
 [Term]
 id: MOD:01420
@@ -25790,8 +25793,8 @@ name: thiazole/thiazoline ring crosslinked residues
 def: "A protein modification that crosslinks two residues by condensation of a cysteine thiol with the carbonyl of the preceding residue to form a thiazole or thiazoline ring." [PubMed:18688235]
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00687
-is_a: MOD:00690
+is_a: MOD:00687 ! thioether crosslinked residues
+is_a: MOD:00690 ! oxazole/thiazole ring crosslinked residues
 
 [Term]
 id: MOD:01421
@@ -25799,8 +25802,8 @@ name: oxazole/oxazoline ring crosslinked residues (Ser)
 def: "A protein modification that crosslinks two residues by condensation of a serine hydroxyl with the carbonyl of the preceding residue to form an oxazole or oxazoline ring." [PubMed:18688235]
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:02055
-is_a: MOD:01419
+is_a: MOD:02055 ! crosslinked L-serine residue
+is_a: MOD:01419 ! oxazole/oxazoline ring crosslinked residues
 
 [Term]
 id: MOD:01422
@@ -25808,8 +25811,8 @@ name: oxazole/oxazoline ring crosslinked residues (Thr)
 def: "A protein modification that crosslinks two residues by condensation of a threonine hydroxyl with the carbonyl of the preceding residue to form a 5-methyloxazole or 5-methyloxazoline ring." [PubMed:18688235]
 property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:02056
-is_a: MOD:01419
+is_a: MOD:02056 ! crosslinked L-threonine residue
+is_a: MOD:01419 ! oxazole/oxazoline ring crosslinked residues
 
 [Term]
 id: MOD:01423
@@ -25822,14 +25825,14 @@ property_value: DiffMono "236.214016" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:431
-is_a: MOD:00649
-is_a: MOD:01155
+is_a: MOD:00649 ! acylated residue
+is_a: MOD:01155 ! lipoconjugated residue
 
 [Term]
 id: MOD:01424
 name: quinaldate modified residue
 def: "A protein modification that effectively results from forming an adduct with a compound containing a quinaldate, kynurenate, or xanthurenate group." [PubMed:18688235]
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:01425
@@ -25838,14 +25841,14 @@ def: "A protein modification that crosslinks three residues by formation of a py
 comment: Cross-link 3.
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00033
+is_a: MOD:00033 ! crosslinked residues
 
 [Term]
 id: MOD:01426
 name: isotope tagged reagent derivatized residue
 def: "A protein modification that forms an adduct with a particular isotope labeled compound used as a reagent." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01427
@@ -25865,32 +25868,32 @@ id: MOD:01428
 name: (13)C isotope tagged reagent
 def: "A protein modification that forms an adduct with a (13)C labeled compound used as a reagent." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:01426
-is_a: MOD:00842
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
+is_a: MOD:00842 ! (13)C labeled residue
 
 [Term]
 id: MOD:01429
 name: (15)N isotope tagged reagent
 def: "A protein modification that forms an adduct with a (15)N labeled compound used as a reagent." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:01426
-is_a: MOD:00843
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
+is_a: MOD:00843 ! (15)N labeled residue
 
 [Term]
 id: MOD:01430
 name: (18)O isotope tagged reagent
 def: "A protein modification that forms an adduct with a (13)C labeled compound used as a reagent." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:01426
-is_a: MOD:00844
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
+is_a: MOD:00844 ! (18)O labeled residue
 
 [Term]
 id: MOD:01431
 name: (2)H deuterium tagged reagent
 def: "A protein modification that forms an adduct with a (2)H labeled compound used as a reagent." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:01426
-is_a: MOD:00839
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
+is_a: MOD:00839 ! (2)H deuterium labeled residue
 
 [Term]
 id: MOD:01432
@@ -25910,7 +25913,7 @@ property_value: MassMono "145.073893" xsd:float
 property_value: Origin "L" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0666
-is_a: MOD:01412
+is_a: MOD:01412 ! dihydroxylated leucine
 
 [Term]
 id: MOD:01433
@@ -25931,8 +25934,8 @@ property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0379
-is_a: MOD:00683
-is_a: MOD:00917
+is_a: MOD:00683 ! dehydrogenated residue
+is_a: MOD:00917 ! modified L-threonine residue
 
 [Term]
 id: MOD:01434
@@ -25952,8 +25955,8 @@ property_value: MassMono "145.037508" xsd:float
 property_value: Origin "E" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0453
-is_a: MOD:00425
-is_a: MOD:00906
+is_a: MOD:00425 ! monohydroxylated residue
+is_a: MOD:00906 ! modified L-glutamic acid residue
 
 [Term]
 id: MOD:01435
@@ -25972,9 +25975,9 @@ property_value: MassAvg "401.44" xsd:float
 property_value: MassMono "401.104542" xsd:float
 property_value: Origin "C, E" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00672
-is_a: MOD:02044
-is_a: MOD:02045
+is_a: MOD:00672 ! S-acylated residue
+is_a: MOD:02044 ! crosslinked L-cysteine residue
+is_a: MOD:02045 ! crosslinked L-glutamic acid residue
 
 [Term]
 id: MOD:01436
@@ -25993,7 +25996,7 @@ property_value: MassMono "286.086152" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
-is_a: MOD:01629
+is_a: MOD:01629 ! cyclo[(prolylserin)-O-yl] cysteinate
 
 [Term]
 id: MOD:01437
@@ -26014,10 +26017,10 @@ property_value: Origin "C, P, S" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0380
-is_a: MOD:02054
-is_a: MOD:02055
-is_a: MOD:01629
-is_a: MOD:00954
+is_a: MOD:02054 ! crosslinked L-proline residue
+is_a: MOD:02055 ! crosslinked L-serine residue
+is_a: MOD:01629 ! cyclo[(prolylserin)-O-yl] cysteinate
+is_a: MOD:00954 ! crosslinked residues with loss of water
 
 [Term]
 id: MOD:01438
@@ -26038,7 +26041,7 @@ property_value: MassAvg "208.28" xsd:float
 property_value: MassMono "208.067034" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00424
+is_a: MOD:00424 ! S-pyridylethyl-L-cysteine
 
 [Term]
 id: MOD:01439
@@ -26051,7 +26054,7 @@ synonym: "S-(pyridin-4-ylethyl)-L-cysteine" EXACT PSI-MOD-alternate []
 synonym: "S-pyridylethylation" RELATED Unimod-description []
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00424
+is_a: MOD:00424 ! S-pyridylethyl-L-cysteine
 
 [Term]
 id: MOD:01440
@@ -26064,8 +26067,8 @@ property_value: MassAvg "113.12" xsd:float
 property_value: MassMono "113.047678" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00859
-is_a: MOD:00594
+is_a: MOD:00859 ! modified residue that can arise from different natural residues
+is_a: MOD:00594 ! residues isobaric at 113.047678 Da
 
 [Term]
 id: MOD:01441
@@ -26074,7 +26077,7 @@ def: "A protein modification that inserts or replaces a residue with a natural,
 subset: PSI-MOD-slim
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00009
+is_a: MOD:00009 ! natural residue
 
 [Term]
 id: MOD:01442
@@ -26093,9 +26096,9 @@ property_value: MassMono "260.116092" xsd:float
 property_value: Origin "V, Y" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0390
-is_a: MOD:00692
-is_a: MOD:02058
-is_a: MOD:02059
+is_a: MOD:00692 ! uncategorized crosslinked residues
+is_a: MOD:02058 ! crosslinked L-tyrosine residue
+is_a: MOD:02059 ! crosslinked L-valine residue
 
 [Term]
 id: MOD:01443
@@ -26111,11 +26114,11 @@ property_value: MassAvg "1140.86" xsd:float
 property_value: MassMono "1140.326447" xsd:float
 property_value: Origin "E, E, E, E, H, H" xsd:string
 property_value: Source "natural" xsd:string
-relationship: contains MOD:00438
-is_a: MOD:00738
-is_a: MOD:00740
-is_a: MOD:02068
-is_a: MOD:02070
+relationship: contains MOD:00438 ! myristoylated residue
+is_a: MOD:00738 ! iron containing modified residue
+is_a: MOD:00740 ! manganese containing modified residue
+is_a: MOD:02068 ! metal or metal cluster coordinated L-glutamic acid residue
+is_a: MOD:02070 ! metal or metal cluster coordinated L-histidine residue
 
 [Term]
 id: MOD:01444
@@ -26136,8 +26139,8 @@ property_value: MassAvg "103.08" xsd:float
 property_value: MassMono "103.026943" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00905
-is_a: MOD:01448
+is_a: MOD:00905 ! modified L-cysteine residue
+is_a: MOD:01448 ! L-3,3-dihydroxyoalanine
 
 [Term]
 id: MOD:01445
@@ -26158,8 +26161,8 @@ property_value: MassAvg "103.08" xsd:float
 property_value: MassMono "103.026943" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00916
-is_a: MOD:01448
+is_a: MOD:00916 ! modified L-serine residue
+is_a: MOD:01448 ! L-3,3-dihydroxyoalanine
 
 [Term]
 id: MOD:01446
@@ -26178,8 +26181,8 @@ property_value: MassMono "178.053789" xsd:float
 property_value: Origin "MOD:00030" xsd:string
 property_value: Source "hypothetical" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:01450
-relationship: derives_from MOD:00030
+is_a: MOD:01450 ! modified N-formyl-L-methionine residue
+relationship: derives_from MOD:00030 ! N-formyl-L-methionine residue
 
 [Term]
 id: MOD:01447
@@ -26199,7 +26202,7 @@ property_value: MassMono "178.053789" xsd:float
 property_value: Origin "M" xsd:string
 property_value: Source "hypothetical" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00913
+is_a: MOD:00913 ! modified L-methionine residue
 
 [Term]
 id: MOD:01448
@@ -26217,7 +26220,7 @@ property_value: MassAvg "103.08" xsd:float
 property_value: MassMono "103.026943" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00859
+is_a: MOD:00859 ! modified residue that can arise from different natural residues
 
 [Term]
 id: MOD:01449
@@ -26231,8 +26234,8 @@ property_value: MassAvg "103.08" xsd:float
 property_value: MassMono "103.026943" xsd:float
 property_value: Origin "MOD:01169" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:01448
-relationship: derives_from MOD:01169
+is_a: MOD:01448 ! L-3,3-dihydroxyoalanine
+relationship: derives_from MOD:01169 ! L-3-oxoalanine
 
 [Term]
 id: MOD:01450
@@ -26240,8 +26243,8 @@ name: modified N-formyl-L-methionine residue
 def: "A protein modification that modifies an N-formyl-L-methionine residue." [PubMed:18688235]
 property_value: Origin "MOD:00030" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:01157
-relationship: derives_from MOD:00030
+is_a: MOD:01157 ! protein modification categorized by amino acid modified
+relationship: derives_from MOD:00030 ! N-formyl-L-methionine residue
 
 [Term]
 id: MOD:01451
@@ -26257,9 +26260,9 @@ property_value: MassAvg "167.06" xsd:float
 property_value: MassMono "166.998359" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00916
-is_a: MOD:00431
-relationship: derives_from MOD:00159
+is_a: MOD:00916 ! modified L-serine
+is_a: MOD:00431 ! modified residue with a secondary neutral loss
+relationship: derives_from MOD:00159 ! O-phosphopantetheine-L-serine
 
 [Term]
 id: MOD:01452
@@ -26275,9 +26278,9 @@ property_value: MassAvg "167.06" xsd:float
 property_value: MassMono "166.998359" xsd:float
 property_value: Origin "MOD:00159" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00916
-is_a: MOD:00431
-relationship: derives_from MOD:00159
+is_a: MOD:00916 ! modified L-serine
+is_a: MOD:00431 ! modified residue with a secondary neutral loss
+relationship: derives_from MOD:00159 ! O-phosphopantetheine-L-serine
 
 [Term]
 id: MOD:01453
@@ -26300,10 +26303,10 @@ property_value: MassAvg "143.14" xsd:float
 property_value: MassMono "143.058243" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00393
-is_a: MOD:00599
-is_a: MOD:00713
-is_a: MOD:00859
+is_a: MOD:00393 ! O-methylated residue
+is_a: MOD:00599 ! monomethylated residue
+is_a: MOD:00713 ! methylated glutamic acid
+is_a: MOD:00859 ! modified residue that can arise from different natural residues
 
 [Term]
 id: MOD:01454
@@ -26317,8 +26320,8 @@ property_value: FormalCharge "1+" xsd:string
 property_value: Origin "P" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00750
-is_a: MOD:00915
+is_a: MOD:00750 ! deoxyribonucleic acid linked residue
+is_a: MOD:00915 ! modified L-proline residue
 
 [Term]
 id: MOD:01455
@@ -26330,7 +26333,7 @@ property_value: DiffAvg "79.98" xsd:float
 property_value: DiffFormula "H 1 O 3 P 1" xsd:string
 property_value: DiffMono "79.966331" xsd:float
 property_value: Origin "X" xsd:string
-is_a: MOD:00696
+is_a: MOD:00696 ! phosphorylated residue
 
 [Term]
 id: MOD:01456
@@ -26342,7 +26345,7 @@ property_value: DiffAvg "79.98" xsd:float
 property_value: DiffFormula "H 1 O 3 P 1" xsd:string
 property_value: DiffMono "79.966331" xsd:float
 property_value: Origin "X" xsd:string
-is_a: MOD:00696
+is_a: MOD:00696 ! phosphorylated residue
 
 [Term]
 id: MOD:01457
@@ -26357,9 +26360,9 @@ property_value: MassAvg "103.14" xsd:float
 property_value: MassMono "103.009185" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00749
-is_a: MOD:00916
-is_a: MOD:02088
+is_a: MOD:00749 ! sulfur substitution for oxygen
+is_a: MOD:00916 ! modified L-serine residue
+is_a: MOD:02088 ! natural, standard, encoded residue substitution
 
 [Term]
 id: MOD:01458
@@ -26375,8 +26378,8 @@ property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:1
-is_a: MOD:00408
-is_a: MOD:01696
+is_a: MOD:00408 ! mono N-acetylated residue
+is_a: MOD:01696 ! alpha-amino acylated residue
 
 [Term]
 id: MOD:01459
@@ -26394,7 +26397,7 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:199
-is_a: MOD:00552
+is_a: MOD:00552 ! 4x(2)H labeled dimethylated residue
 
 [Term]
 id: MOD:01460
@@ -26405,7 +26408,7 @@ synonym: "N2MeRes" EXACT PSI-MOD-label []
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00602
+is_a: MOD:00602 ! N-methylated residue
 
 [Term]
 id: MOD:01461
@@ -26414,8 +26417,8 @@ def: "A protein modification that effectively replaces an L-alanine alpha amino
 subset: PSI-MOD-slim
 property_value: Origin "A" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00665
-is_a: MOD:01460
+is_a: MOD:00665 ! methylated alanine
+is_a: MOD:01460 ! alpha-amino methylated residue
 
 [Term]
 id: MOD:01462
@@ -26425,8 +26428,8 @@ subset: PSI-MOD-slim
 property_value: Origin "P" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00712
-is_a: MOD:01460
+is_a: MOD:00712 ! methylated proline
+is_a: MOD:01460 ! alpha-amino methylated residue
 
 [Term]
 id: MOD:01463
@@ -26436,8 +26439,8 @@ subset: PSI-MOD-slim
 property_value: Origin "M" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00716
-is_a: MOD:01460
+is_a: MOD:00716 ! methylated methionine
+is_a: MOD:01460 ! alpha-amino methylated residue
 
 [Term]
 id: MOD:01464
@@ -26454,8 +26457,8 @@ property_value: MassMono "133.055586" xsd:float
 property_value: Origin "M" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00913
-is_a: MOD:01700
+is_a: MOD:00913 ! modified L-methionine residue
+is_a: MOD:01700 ! alpha-amino protonated residue
 
 [Term]
 id: MOD:01465
@@ -26474,8 +26477,8 @@ property_value: MassMono "175.102537" xsd:float
 property_value: Origin "MOD:001464" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:01687
-relationship: derives_from MOD:01464
+is_a: MOD:01687 ! alpha-amino trimethylated residue
+relationship: derives_from MOD:01464 ! protonated L-methionine (L-methioninium) residue
 
 [Term]
 id: MOD:01466
@@ -26492,8 +26495,8 @@ property_value: MassMono "273.045964" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:302
-is_a: MOD:00621
-is_a: MOD:00905
+is_a: MOD:00621 ! menadione quinone derivative
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:01467
@@ -26510,8 +26513,8 @@ property_value: MassMono "298.131742" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:302
-is_a: MOD:00621
-is_a: MOD:00912
+is_a: MOD:00621 ! menadione quinone derivative
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:01468
@@ -26534,8 +26537,8 @@ property_value: MassMono "1723.939410" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:415
-is_a: MOD:00744
-is_a: MOD:02073
+is_a: MOD:00744 ! molybdenum pterin containing modification
+is_a: MOD:02073 ! metal or metal cluster coordinated L-selenocysteine residue
 
 [Term]
 id: MOD:01469
@@ -26550,9 +26553,9 @@ property_value: MassAvg "1842.02" xsd:float
 property_value: MassMono "1841.957004" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00746
-is_a: MOD:00748
-is_a: MOD:02073
+is_a: MOD:00746 ! tungsten containing modified residue
+is_a: MOD:00748 ! pterin modified residue
+is_a: MOD:02073 ! metal or metal cluster coordinated L-selenocysteine residue
 
 [Term]
 id: MOD:01470
@@ -26583,7 +26586,7 @@ property_value: MassMono "83.037114" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0441
-is_a: MOD:00190
+is_a: MOD:00190 ! dehydrobutyrine (Thr)
 
 [Term]
 id: MOD:01471
@@ -26614,7 +26617,7 @@ property_value: MassMono "83.037114" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0440
-is_a: MOD:00190
+is_a: MOD:00190 ! dehydrobutyrine (Thr)
 
 [Term]
 id: MOD:01472
@@ -26622,7 +26625,7 @@ name: reduced residue
 def: "A protein modification that effectively either adds neutral hydrogen atoms (proton and electron), or removes oxygen atoms from a residue with or without the addition of hydrogen atoms." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "RedRes" EXACT PSI-MOD-label []
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:01473
@@ -26630,7 +26633,7 @@ name: hydrogenated residue
 def: "A protein modification that effectively adds neutral hydrogen atoms (proton and electron) to a residue." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "HRes" EXACT PSI-MOD-label []
-is_a: MOD:01472
+is_a: MOD:01472 ! reduced residue
 
 [Term]
 id: MOD:01474
@@ -26645,10 +26648,10 @@ property_value: MassAvg "485.44" xsd:float
 property_value: MassMono "485.123302" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
-relationship: derives_from MOD:00399
-is_a: MOD:00861
-is_a: MOD:00916
-relationship: derives_from MOD:00159
+relationship: derives_from MOD:00399 ! iodoacetic acid derivatized residue
+is_a: MOD:00861 ! phosphorus containing modified residue
+is_a: MOD:00916 ! modified L-serine residue
+relationship: derives_from MOD:00159 ! O-phosphopantetheine-L-serine
 
 [Term]
 id: MOD:01475
@@ -26663,10 +26666,10 @@ property_value: MassAvg "484.46" xsd:float
 property_value: MassMono "484.139286" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
-relationship: derives_from MOD:00397
-is_a: MOD:00861
-is_a: MOD:00916
-relationship: derives_from MOD:00159
+relationship: derives_from MOD:00397 ! iodoacetamide derivatized residue
+is_a: MOD:00861 ! phosphorus containing modified residue
+is_a: MOD:00916 ! modified L-serine residue
+relationship: derives_from MOD:00159 ! O-phosphopantetheine-L-serine
 
 [Term]
 id: MOD:01476
@@ -26683,7 +26686,7 @@ property_value: MassAvg "165.17" xsd:float
 property_value: MassMono "165.058992" xsd:float
 property_value: Origin "F" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01227
+is_a: MOD:01227 ! monofluorinated L-phenylalanine
 
 [Term]
 id: MOD:01477
@@ -26700,7 +26703,7 @@ property_value: MassAvg "165.17" xsd:float
 property_value: MassMono "165.058992" xsd:float
 property_value: Origin "F" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01227
+is_a: MOD:01227 ! monofluorinated L-phenylalanine
 
 [Term]
 id: MOD:01478
@@ -26718,7 +26721,7 @@ property_value: MassAvg "165.17" xsd:float
 property_value: MassMono "165.058992" xsd:float
 property_value: Origin "F" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01227
+is_a: MOD:01227 ! monofluorinated L-phenylalanine
 
 [Term]
 id: MOD:01479
@@ -26733,7 +26736,7 @@ property_value: MassAvg "204.20" xsd:float
 property_value: MassMono "204.069891" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01226
+is_a: MOD:01226 ! monofluorinated L-tryptophan
 
 [Term]
 id: MOD:01480
@@ -26748,7 +26751,7 @@ property_value: MassAvg "204.20" xsd:float
 property_value: MassMono "204.069891" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01226
+is_a: MOD:01226 ! monofluorinated L-tryptophan
 
 [Term]
 id: MOD:01481
@@ -26763,7 +26766,7 @@ property_value: MassAvg "204.20" xsd:float
 property_value: MassMono "204.069891" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01226
+is_a: MOD:01226 ! monofluorinated L-tryptophan
 
 [Term]
 id: MOD:01482
@@ -26771,7 +26774,7 @@ name: calcium containing modified residue
 def: "A protein modification that effectively substitutes a calcium atom or a cluster containing calcium for hydrogen atoms, or that coordinates a calcium ion." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "CaRes" EXACT PSI-MOD-label []
-is_a: MOD:00698
+is_a: MOD:00698 ! metal or metal cluster containing modified residue
 
 [Term]
 id: MOD:01483
@@ -26783,8 +26786,8 @@ property_value: DiffFormula "C 1 O 1" xsd:string
 property_value: DiffMono "27.994915" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00493
-is_a: MOD:00671
+is_a: MOD:00493 ! formylated residue
+is_a: MOD:00671 ! O-acylated residue
 
 [Term]
 id: MOD:01484
@@ -26805,9 +26808,9 @@ property_value: MassAvg "239.27" xsd:float
 property_value: MassMono "239.126991" xsd:float
 property_value: Origin "K, E" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:02045
-is_a: MOD:00954
-is_a: MOD:01630
+is_a: MOD:02045 ! crosslinked L-glutamic acid residue
+is_a: MOD:00954 ! crosslinked residues with loss of water
+is_a: MOD:01630 ! N6-(L-isoglutamyl)-L-lysine
 
 [Term]
 id: MOD:01485
@@ -26826,10 +26829,10 @@ property_value: DiffMono "144.105919" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:532
-is_a: MOD:01428
-is_a: MOD:01430
-is_a: MOD:01516
-is_a: MOD:01518
+is_a: MOD:01428 ! (13)C isotope tagged reagent
+is_a: MOD:01430 ! (18)O isotope tagged reagent
+is_a: MOD:01516 ! modifications with monoisotopic mass diferences that are nominally equal at 144.099-144.106 Da.
+is_a: MOD:01518 ! iTRAQ4plex reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01486
@@ -26850,8 +26853,8 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:532
-is_a: MOD:01485
-is_a: MOD:01711
+is_a: MOD:01485 ! iTRAQ4plex-114 reporter+balance reagent acylated residue
+is_a: MOD:01711 ! iTRAQ4plex reporter+balance reagent acylated N-terminal
 
 [Term]
 id: MOD:01487
@@ -26874,9 +26877,9 @@ property_value: MassMono "272.200882" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:532
-is_a: MOD:01485
-is_a: MOD:01709
-is_a: MOD:01875
+is_a: MOD:01485 ! iTRAQ4plex-114 reporter+balance reagent ac ylated residue
+is_a: MOD:01709 ! iTRAQ4plex reporter+balance reagent N-acylated residue
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01488
@@ -26898,9 +26901,9 @@ property_value: MassMono "307.169248" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:532
-is_a: MOD:00919
-is_a: MOD:01485
-is_a: MOD:01713
+is_a: MOD:00919 ! modified L-tyrosine residue
+is_a: MOD:01485 ! iTRAQ4plex-114 reporter+balance reagent acylated residue
+is_a: MOD:01713 ! iTRAQ4plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01489
@@ -26917,9 +26920,9 @@ property_value: MassAvg "281.16" xsd:float
 property_value: MassMono "281.164831" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00909
-is_a: MOD:01485
-is_a: MOD:01709
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:01485 ! iTRAQ4plex-114 reporter+balance reagent acylated residue
+is_a: MOD:01709 ! iTRAQ4plex reporter+balance reagent N-acylated residue
 
 [Term]
 id: MOD:01490
@@ -26936,9 +26939,9 @@ property_value: MassAvg "231.14" xsd:float
 property_value: MassMono "231.137947" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02003
-is_a: MOD:01485
-is_a: MOD:01713
+is_a: MOD:02003 ! O3-acylated L-serine
+is_a: MOD:01485 ! iTRAQ4plex-114 reporter+balance reagent acylated residue
+is_a: MOD:01713 ! iTRAQ4plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01491
@@ -26955,9 +26958,9 @@ property_value: MassAvg "245.15" xsd:float
 property_value: MassMono "245.153598" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02004
-is_a: MOD:01485
-is_a: MOD:01713
+is_a: MOD:02004 ! O3-acylated L-threonine
+is_a: MOD:01485 ! iTRAQ4plex-114 reporter+balance reagent acylated residue
+is_a: MOD:01713 ! iTRAQ4plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01492
@@ -26976,11 +26979,11 @@ property_value: DiffMono "144.099599" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:533
-is_a: MOD:01428
-is_a: MOD:01429
-is_a: MOD:01430
-is_a: MOD:01516
-is_a: MOD:01518
+is_a: MOD:01428 ! (13)C isotope tagged reagent
+is_a: MOD:01429 ! (15)N isotope tagged reagent
+is_a: MOD:01430 ! (18)O isotope tagged reagent
+is_a: MOD:01516 ! modifications with monoisotopic mass diferences that are nominally equal at 144.099-144.106 Da.
+is_a: MOD:01518 ! iTRAQ4plex reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01493
@@ -27001,8 +27004,8 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:533
-is_a: MOD:01492
-is_a: MOD:01711
+is_a: MOD:01492 ! iTRAQ4plex-115 reporter+balance reagent acylated residue
+is_a: MOD:01711 ! iTRAQ4plex reporter+balance reagent acylated N-terminal
 
 [Term]
 id: MOD:01494
@@ -27025,9 +27028,9 @@ property_value: MassMono "272.194562" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:533
-is_a: MOD:01492
-is_a: MOD:01709
-is_a: MOD:01875
+is_a: MOD:01492 ! iTRAQ4plex-115 reporter+balance reagent acylated residue
+is_a: MOD:01709 ! iTRAQ4plex reporter+balance reagent N-acylated residue
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01495
@@ -27049,9 +27052,9 @@ property_value: MassMono "307.162928" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:533
-is_a: MOD:00919
-is_a: MOD:01492
-is_a: MOD:01713
+is_a: MOD:00919 ! modified L-tyrosine residue
+is_a: MOD:01492 ! iTRAQ4plex-115 reporter+balance reagent acylated residue
+is_a: MOD:01713 ! iTRAQ4plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01496
@@ -27068,9 +27071,9 @@ property_value: MassAvg "281.16" xsd:float
 property_value: MassMono "281.158511" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00909
-is_a: MOD:01492
-is_a: MOD:01709
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:01492 ! iTRAQ4plex-115 reporter+balance reagent acylated residue
+is_a: MOD:01709 ! iTRAQ4plex reporter+balance reagent N-acylated residue
 
 [Term]
 id: MOD:01497
@@ -27087,9 +27090,9 @@ property_value: MassAvg "231.13" xsd:float
 property_value: MassMono "231.131628" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02003
-is_a: MOD:01492
-is_a: MOD:01713
+is_a: MOD:02003 ! O3-acylated L-serine
+is_a: MOD:01492 ! iTRAQ4plex-115 reporter+balance reagent acylated residue
+is_a: MOD:01713 ! iTRAQ4plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01498
@@ -27106,9 +27109,9 @@ property_value: MassAvg "245.15" xsd:float
 property_value: MassMono "245.147278" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02004
-is_a: MOD:01492
-is_a: MOD:01713
+is_a: MOD:02004 ! O3-acylated L-threonine
+is_a: MOD:01492 ! iTRAQ4plex-115 reporter+balance reagent acylated residue
+is_a: MOD:01713 ! iTRAQ4plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01499
@@ -27127,10 +27130,10 @@ property_value: DiffMono "144.102062" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:214
-is_a: MOD:01428
-is_a: MOD:01429
-is_a: MOD:01517
-is_a: MOD:01518
+is_a: MOD:01428 ! (13)C isotope tagged reagent
+is_a: MOD:01429 ! (15)N isotope tagged reagent
+is_a: MOD:01517 ! modifications with monoisotopic mass differences that are nominally equal at 144.102062 Da
+is_a: MOD:01518 ! iTRAQ4plex reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01500
@@ -27151,8 +27154,8 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:214
-is_a: MOD:01499
-is_a: MOD:01711
+is_a: MOD:01499 ! iTRAQ4plex-116 reporter+balance reagent acylated residue
+is_a: MOD:01711 ! iTRAQ4plex reporter+balance reagent acylated N-terminal
 
 [Term]
 id: MOD:01501
@@ -27175,9 +27178,9 @@ property_value: MassMono "272.197025" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:214
-is_a: MOD:01499
-is_a: MOD:01709
-is_a: MOD:01875
+is_a: MOD:01499 ! iTRAQ4plex-116 reporter+balance reagent acylated residue
+is_a: MOD:01709 ! iTRAQ4plex reporter+balance reagent N-acylated residue
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01502
@@ -27199,9 +27202,9 @@ property_value: MassMono "307.165391" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:214
-is_a: MOD:00919
-is_a: MOD:01499
-is_a: MOD:01713
+is_a: MOD:00919 ! modified L-tyrosine residue
+is_a: MOD:01499 ! iTRAQ4plex-116 reporter+balance reagent acylated residue
+is_a: MOD:01713 ! iTRAQ4plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01503
@@ -27218,9 +27221,9 @@ property_value: MassAvg "281.16" xsd:float
 property_value: MassMono "281.160974" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00909
-is_a: MOD:01499
-is_a: MOD:01709
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:01499 ! iTRAQ4plex-116 reporter+balance reagent acylated residue
+is_a: MOD:01709 ! iTRAQ4plex reporter+balance reagent N-acylated residue
 
 [Term]
 id: MOD:01504
@@ -27237,9 +27240,9 @@ property_value: MassAvg "231.13" xsd:float
 property_value: MassMono "231.134091" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02003
-is_a: MOD:01499
-is_a: MOD:01713
+is_a: MOD:02003 ! O3-acylated L-serine
+is_a: MOD:01499 ! iTRAQ4plex-116 reporter+balance reagent acylated residue
+is_a: MOD:01713 ! iTRAQ4plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01505
@@ -27256,9 +27259,9 @@ property_value: MassAvg "245.15" xsd:float
 property_value: MassMono "245.149741" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02004
-is_a: MOD:01499
-is_a: MOD:01713
+is_a: MOD:02004 ! O3-acylated L-threonine
+is_a: MOD:01499 ! iTRAQ4plex-116 reporter+balance reagent acylated residue
+is_a: MOD:01713 ! iTRAQ4plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01506
@@ -27280,11 +27283,11 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:214
 xref: Unimod:889
-is_a: MOD:01428
-is_a: MOD:01429
-is_a: MOD:01517
-is_a: MOD:01518
-is_a: MOD:01863
+is_a: MOD:01428 ! (13)C isotope tagged reagent
+is_a: MOD:01429 ! (15)N isotope tagged reagent
+is_a: MOD:01517 ! modifications with monoisotopic mass differences that are nominally equal at 144.102062 Da
+is_a: MOD:01518 ! iTRAQ4plex reporter+balance reagent acylated residue
+is_a: MOD:01863 ! mTRAQ reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01507
@@ -27309,8 +27312,8 @@ property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:214
 xref: Unimod:889
-is_a: MOD:01506
-is_a: MOD:01711
+is_a: MOD:01506 ! iTRAQ4plex-117, mTRAQ heavy, reporter+balance reagent acylated residue
+is_a: MOD:01711 ! iTRAQ4plex reporter+balance reagent acylated N-terminal
 
 [Term]
 id: MOD:01508
@@ -27336,9 +27339,9 @@ property_value: MassMono "272.197025" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:214
-is_a: MOD:01506
-is_a: MOD:01709
-is_a: MOD:01875
+is_a: MOD:01506 ! iTRAQ4plex-117, mTRAQ heavy, reporter+balance reagent acylated residue
+is_a: MOD:01709 ! iTRAQ4plex reporter+balance reagent N-acylated residue
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01509
@@ -27364,9 +27367,9 @@ property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:214
 xref: Unimod:889
-is_a: MOD:00919
-is_a: MOD:01506
-is_a: MOD:01713
+is_a: MOD:00919 ! modified L-tyrosine residue
+is_a: MOD:01506 ! iTRAQ4plex-117, mTRAQ heavy, reporter+balance reagent acylated residue
+is_a: MOD:01713 ! iTRAQ4plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01510
@@ -27383,9 +27386,9 @@ property_value: MassAvg "281.16" xsd:float
 property_value: MassMono "281.160974" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00909
-is_a: MOD:01506
-is_a: MOD:01709
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:01506 ! iTRAQ4plex-117, mTRAQ heavy, reporter+balance reagent acylated residue
+is_a: MOD:01709 ! iTRAQ4plex reporter+balance reagent N-acylated residue
 
 [Term]
 id: MOD:01511
@@ -27402,9 +27405,9 @@ property_value: MassAvg "231.13" xsd:float
 property_value: MassMono "231.134091" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02003
-is_a: MOD:01506
-is_a: MOD:01713
+is_a: MOD:02003 ! O3-acylated L-serine
+is_a: MOD:01506 ! iTRAQ4plex-117, mTRAQ heavy, reporter+balance reagent acylated residue
+is_a: MOD:01713 ! iTRAQ4plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01512
@@ -27421,45 +27424,45 @@ property_value: MassAvg "245.15" xsd:float
 property_value: MassMono "245.149741" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02004
-is_a: MOD:01506
-is_a: MOD:01713
+is_a: MOD:02004 ! O3-acylated L-threonine
+is_a: MOD:01506 ! iTRAQ4plex-117, mTRAQ heavy, reporter+balance reagent acylated residue
+is_a: MOD:01713 ! iTRAQ4plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01513
 name: modifications with monoisotopic mass differences that are nominally equal at a resolution below 0.1 Da
 def: "Modifications that have monoisotopic mass differences from their respective origins that are nominally equal (sometimes called isobaric) at a resolution below 0.1 Da." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00538
+is_a: MOD:00538 ! protein modification categorized by isobaric sets
 
 [Term]
 id: MOD:01514
 name: modifications with monoisotopic mass differences that are nominally equal at a resolution below 0.01 Da
 def: "Modifications that have monoisotopic mass differences from their respective origins that are nominally equal (sometimes called isobaric) at a resolution below 0.01 Da." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:01513
+is_a: MOD:01513 ! modifications with monoisotopic mass differences that are nominally equal at a resolution below 0.1 Da
 
 [Term]
 id: MOD:01515
 name: modifications with monoisotopic mass differences that are nominally equal at a resolution below 0.000001 Da
 def: "Modifications that have monoisotopic mass differences from their respective origins that are nominally equal (sometimes called isobaric) at a resolution below 0.000001 Da." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:01514
+is_a: MOD:01514 ! modifications with monoisotopic mass differences that are nominally equal at a resolution below 0.01 Da
 
 [Term]
 id: MOD:01516
 name: modifications with monoisotopic mass diferences that are nominally equal at 144.099-144.106 Da.
 def: "Modifications that have monoisotopic mass differences from their respective origins of 144.099-144.106 Da." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:01514
+is_a: MOD:01514 ! modifications with monoisotopic mass differences that are nominally equal at a resolution below 0.01 Da
 
 [Term]
 id: MOD:01517
 name: modifications with monoisotopic mass differences that are nominally equal at 144.102062 Da
 def: "Modifications that have monoisotopic mass differences from their respective origins of 144.102062 Da." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:01515
-is_a: MOD:01516
+is_a: MOD:01515 ! modifications with monoisotopic mass differences that are nominally equal at a resolution below 0.000001 Da
+is_a: MOD:01516 ! modifications with monoisotopic mass diferences that are nominally equal at 144.099-144.106 Da.
 
 [Term]
 id: MOD:01518
@@ -27471,8 +27474,8 @@ synonym: "(4-methylpiperazin-1-yl)acetyl" EXACT PSI-MOD-alternate []
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:214
-is_a: MOD:01426
-is_a: MOD:01705
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
+is_a: MOD:01705 ! isotope tagged reagent acylated residue
 
 [Term]
 id: MOD:01519
@@ -27480,21 +27483,21 @@ name: reporter fragment
 def: "A distinct molecular entity produced from a protein or a protein modification as the result of a fragmentation process." [PubMed:18688235]
 comment: The reporter fragment is either itself a modification consisting of atoms derived from the original amino acid residues, or its detection can be taken as evidence that particular modified residues had been present.
 subset: PSI-MOD-slim
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:01520
 name: modification reporter fragment
 def: "A distinct molecular entity produced as the result of a fragmentation process performed on a particular modified residue." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:01519
+is_a: MOD:01519 ! reporter fragment
 
 [Term]
 id: MOD:01521
 name: iTRAQ4plex reporter fragment
 def: "A protein modification reporter fragment produced by an Applied Biosystems iTRAQ4plex reagent derivatized residue." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:01520
+is_a: MOD:01520 ! modification reporter fragment
 
 [Term]
 id: MOD:01522
@@ -27508,8 +27511,8 @@ property_value: MassAvg "114.11" xsd:float
 property_value: MassMono "114.110680" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01521
-relationship: derives_from MOD:01485
+is_a: MOD:01521 ! iTRAQ4plex reporter fragment
+relationship: derives_from MOD:01485 ! iTRAQ4plex-114 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01523
@@ -27523,8 +27526,8 @@ property_value: MassAvg "115.11" xsd:float
 property_value: MassMono "115.107715" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01521
-relationship: derives_from MOD:01492
+is_a: MOD:01521 ! iTRAQ4plex reporter fragment
+relationship: derives_from MOD:01492 ! iTRAQ4plex-115 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01524
@@ -27538,8 +27541,8 @@ property_value: MassAvg "116.11" xsd:float
 property_value: MassMono "116.111069" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01521
-relationship: derives_from MOD:01499
+is_a: MOD:01521 ! iTRAQ4plex reporter fragment
+relationship: derives_from MOD:01499 ! iTRAQ4plex-116 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01525
@@ -27553,9 +27556,9 @@ property_value: MassAvg "117.11" xsd:float
 property_value: MassMono "117.114424" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01521
-is_a: MOD:01870
-relationship: derives_from MOD:01506
+is_a: MOD:01521 ! iTRAQ4plex reporter fragment
+is_a: MOD:01870 ! mTRAQ reporter fragment
+relationship: derives_from MOD:01506 ! iTRAQ4plex-117, mTRAQ heavy, reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01526
@@ -27566,15 +27569,15 @@ subset: PSI-MOD-slim
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:730
-is_a: MOD:01426
-is_a: MOD:01705
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
+is_a: MOD:01705 ! isotope tagged reagent acylated residue
 
 [Term]
 id: MOD:01527
 name: residue reporter fragment
 def: "A distinct molecular entity produced from a particular amino acid residue as the result of a fragmentation process." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:01519
+is_a: MOD:01519 ! reporter fragment
 
 [Term]
 id: MOD:01528
@@ -27593,10 +27596,10 @@ property_value: DiffMono "304.205359" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:730
-is_a: MOD:01428
-is_a: MOD:01429
-is_a: MOD:01526
-is_a: MOD:01591
+is_a: MOD:01428 ! (13)C isotope tagged reagent
+is_a: MOD:01429 ! (15)N isotope tagged reagent
+is_a: MOD:01526 ! iTRAQ8plex reporter+balance reagent acylated residue
+is_a: MOD:01591 ! modifications with monoisotopic mass differences that are nominally equal at 304.205359 Da
 
 [Term]
 id: MOD:01529
@@ -27616,8 +27619,8 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:730
-is_a: MOD:01528
-is_a: MOD:01712
+is_a: MOD:01528 ! iTRAQ8plex-113 reporter+balance reagent acylated residue
+is_a: MOD:01712 ! iTRAQ8plex reporter+balance reagent acylated N-terminal
 
 [Term]
 id: MOD:01530
@@ -27639,9 +27642,9 @@ property_value: MassMono "432.300322" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:730
-is_a: MOD:01528
-is_a: MOD:01710
-is_a: MOD:01875
+is_a: MOD:01528 ! iTRAQ8plex-113 reporter+balance reagent acylated residue
+is_a: MOD:01710 ! iTRAQ8plex reporter+balance reagent N-acylated residue
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01531
@@ -27662,9 +27665,9 @@ property_value: MassMono "467.268688" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:730
-is_a: MOD:00919
-is_a: MOD:01528
-is_a: MOD:01714
+is_a: MOD:00919 ! modified L-tyrosine residue
+is_a: MOD:01528 ! iTRAQ8plex-113 reporter+balance reagent acylated residue
+is_a: MOD:01714 ! iTRAQ8plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01532
@@ -27684,9 +27687,9 @@ property_value: MassAvg "441.26" xsd:float
 property_value: MassMono "441.264271" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00909
-is_a: MOD:01528
-is_a: MOD:01710
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:01528 ! iTRAQ8plex-113 reporter+balance reagent acylated residue
+is_a: MOD:01710 ! iTRAQ8plex reporter+balance reagent N-acylated residue
 
 [Term]
 id: MOD:01533
@@ -27706,9 +27709,9 @@ property_value: MassAvg "391.24" xsd:float
 property_value: MassMono "391.237388" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02003
-is_a: MOD:01528
-is_a: MOD:01714
+is_a: MOD:02003 ! O3-acylated L-serine
+is_a: MOD:01528 ! iTRAQ8plex-113 reporter+balance reagent acylated residue
+is_a: MOD:01714 ! iTRAQ8plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01534
@@ -27728,9 +27731,9 @@ property_value: MassAvg "405.25" xsd:float
 property_value: MassMono "405.253038" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02004
-is_a: MOD:01528
-is_a: MOD:01714
+is_a: MOD:02004 ! O3-acylated L-threonine
+is_a: MOD:01528 ! iTRAQ8plex-113 reporter+balance reagent acylated residue
+is_a: MOD:01714 ! iTRAQ8plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01535
@@ -27749,10 +27752,10 @@ property_value: DiffMono "304.205359" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:730
-is_a: MOD:01428
-is_a: MOD:01429
-is_a: MOD:01526
-is_a: MOD:01591
+is_a: MOD:01428 ! (13)C isotope tagged reagent
+is_a: MOD:01429 ! (15)N isotope tagged reagent
+is_a: MOD:01526 ! iTRAQ8plex reporter+balance reagent acylated residue
+is_a: MOD:01591 ! modifications with monoisotopic mass differences that are nominally equal at 304.205359 Da
 
 [Term]
 id: MOD:01536
@@ -27772,8 +27775,8 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:730
-is_a: MOD:01535
-is_a: MOD:01712
+is_a: MOD:01535 ! iTRAQ8plex-114 reporter+balance reagent acylated residue
+is_a: MOD:01712 ! iTRAQ8plex reporter+balance reagent acylated N-terminal
 
 [Term]
 id: MOD:01537
@@ -27795,9 +27798,9 @@ property_value: MassMono "432.300322" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:730
-is_a: MOD:01535
-is_a: MOD:01710
-is_a: MOD:01875
+is_a: MOD:01535 ! iTRAQ8plex-114 reporter+balance reagent acylated residue
+is_a: MOD:01710 ! iTRAQ8plex reporter+balance reagent N-acylated residue
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01538
@@ -27818,9 +27821,9 @@ property_value: MassMono "467.268688" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:730
-is_a: MOD:00919
-is_a: MOD:01535
-is_a: MOD:01714
+is_a: MOD:00919 ! modified L-tyrosine residue
+is_a: MOD:01535 ! iTRAQ8plex-114 reporter+balance reagent acylated residue
+is_a: MOD:01714 ! iTRAQ8plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01539
@@ -27840,9 +27843,9 @@ property_value: MassAvg "441.26" xsd:float
 property_value: MassMono "441.264271" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00909
-is_a: MOD:01535
-is_a: MOD:01710
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:01535 ! iTRAQ8plex-114 reporter+balance reagent acylated residue
+is_a: MOD:01710 ! iTRAQ8plex reporter+balance reagent N-acylated residue
 
 [Term]
 id: MOD:01540
@@ -27858,9 +27861,9 @@ property_value: MassAvg "391.24" xsd:float
 property_value: MassMono "391.237388" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02003
-is_a: MOD:01535
-is_a: MOD:01714
+is_a: MOD:02003 ! O3-acylated L-serine
+is_a: MOD:01535 ! iTRAQ8plex-114 reporter+balance reagent acylated residue
+is_a: MOD:01714 ! iTRAQ8plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01541
@@ -27876,9 +27879,9 @@ property_value: MassAvg "405.25" xsd:float
 property_value: MassMono "405.253038" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02004
-is_a: MOD:01535
-is_a: MOD:01714
+is_a: MOD:02004 ! O3-acylated L-threonine
+is_a: MOD:01535 ! iTRAQ8plex-114 reporter+balance reagent acylated residue
+is_a: MOD:01714 ! iTRAQ8plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01542
@@ -27896,10 +27899,10 @@ property_value: DiffMono "304.199039" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:731
-is_a: MOD:01428
-is_a: MOD:01429
-is_a: MOD:01526
-is_a: MOD:01584
+is_a: MOD:01428 ! (13)C isotope tagged reagent
+is_a: MOD:01429 ! (15)N isotope tagged reagent
+is_a: MOD:01526 ! iTRAQ8plex reporter+balance reagent acylated residue
+is_a: MOD:01584 ! modifications with monoisotopic mass differences that are nominally equal at 304.199039 Da
 
 [Term]
 id: MOD:01543
@@ -27918,8 +27921,8 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:731
-is_a: MOD:01542
-is_a: MOD:01712
+is_a: MOD:01542 ! iTRAQ8plex-115 reporter+balance reagent acylated residue
+is_a: MOD:01712 ! iTRAQ8plex reporter+balance reagent acylated N-terminal
 
 [Term]
 id: MOD:01544
@@ -27940,9 +27943,9 @@ property_value: MassMono "432.294002" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:731
-is_a: MOD:01542
-is_a: MOD:01710
-is_a: MOD:01875
+is_a: MOD:01542 ! iTRAQ8plex-115 reporter+balance reagent acylated residue
+is_a: MOD:01710 ! iTRAQ8plex reporter+balance reagent N-acylated residue
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01545
@@ -27962,9 +27965,9 @@ property_value: MassMono "467.262368" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:731
-is_a: MOD:00919
-is_a: MOD:01542
-is_a: MOD:01714
+is_a: MOD:00919 ! modified L-tyrosine residue
+is_a: MOD:01542 ! iTRAQ8plex-115 reporter+balance reagent acylated residue
+is_a: MOD:01714 ! iTRAQ8plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01546
@@ -27980,9 +27983,9 @@ property_value: MassAvg "441.26" xsd:float
 property_value: MassMono "441.257951" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00909
-is_a: MOD:01542
-is_a: MOD:01710
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:01542 ! iTRAQ8plex-115 reporter+balance reagent acylated residue
+is_a: MOD:01710 ! iTRAQ8plex reporter+balance reagent N-acylated residue
 
 [Term]
 id: MOD:01547
@@ -27998,9 +28001,9 @@ property_value: MassAvg "391.23" xsd:float
 property_value: MassMono "391.231068" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02003
-is_a: MOD:01542
-is_a: MOD:01714
+is_a: MOD:02003 ! O3-acylated L-serine
+is_a: MOD:01542 ! iTRAQ8plex-115 reporter+balance reagent acylated residue
+is_a: MOD:01714 ! iTRAQ8plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01548
@@ -28016,9 +28019,9 @@ property_value: MassAvg "405.25" xsd:float
 property_value: MassMono "405.246718" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02004
-is_a: MOD:01542
-is_a: MOD:01714
+is_a: MOD:02004 ! O3-acylated L-threonine
+is_a: MOD:01542 ! iTRAQ8plex-115 reporter+balance reagent acylated residue
+is_a: MOD:01714 ! iTRAQ8plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01549
@@ -28037,10 +28040,10 @@ property_value: DiffMono "304.205359" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:730
-is_a: MOD:01428
-is_a: MOD:01429
-is_a: MOD:01526
-is_a: MOD:01591
+is_a: MOD:01428 ! (13)C isotope tagged reagent
+is_a: MOD:01429 ! (15)N isotope tagged reagent
+is_a: MOD:01526 ! iTRAQ8plex reporter+balance reagent acylated residue
+is_a: MOD:01591 ! modifications with monoisotopic mass differences that are nominally equal at 304.205359 Da
 
 [Term]
 id: MOD:01550
@@ -28060,8 +28063,8 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:730
-is_a: MOD:01549
-is_a: MOD:01712
+is_a: MOD:01549 ! iTRAQ8plex-116 reporter+balance reagent acylated residue
+is_a: MOD:01712 ! iTRAQ8plex reporter+balance reagent acylated N-terminal
 
 [Term]
 id: MOD:01551
@@ -28083,9 +28086,9 @@ property_value: MassMono "432.300322" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:730
-is_a: MOD:01549
-is_a: MOD:01710
-is_a: MOD:01875
+is_a: MOD:01549 ! iTRAQ8plex-116 reporter+balance reagent acylated residue
+is_a: MOD:01710 ! iTRAQ8plex reporter+balance reagent N-acylated residue
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01552
@@ -28106,9 +28109,9 @@ property_value: MassMono "467.268688" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:730
-is_a: MOD:00919
-is_a: MOD:01549
-is_a: MOD:01714
+is_a: MOD:00919 ! modified L-tyrosine residue
+is_a: MOD:01549 ! iTRAQ8plex-116 reporter+balance reagent acylated residue
+is_a: MOD:01714 ! iTRAQ8plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01553
@@ -28124,9 +28127,9 @@ property_value: MassAvg "441.26" xsd:float
 property_value: MassMono "441.264271" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00909
-is_a: MOD:01549
-is_a: MOD:01710
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:01549 ! iTRAQ8plex-116 reporter+balance reagent acylated residue
+is_a: MOD:01710 ! iTRAQ8plex reporter+balance reagent N-acylated residue
 
 [Term]
 id: MOD:01554
@@ -28142,9 +28145,9 @@ property_value: MassAvg "391.24" xsd:float
 property_value: MassMono "391.237388" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02003
-is_a: MOD:01549
-is_a: MOD:01714
+is_a: MOD:02003 ! O3-acylated L-serine
+is_a: MOD:01549 ! iTRAQ8plex-116 reporter+balance reagent acylated residue
+is_a: MOD:01714 ! iTRAQ8plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01555
@@ -28160,9 +28163,9 @@ property_value: MassAvg "405.25" xsd:float
 property_value: MassMono "405.253038" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02004
-is_a: MOD:01549
-is_a: MOD:01714
+is_a: MOD:02004 ! O3-acylated L-threonine
+is_a: MOD:01549 ! iTRAQ8plex-116 reporter+balance reagent acylated residue
+is_a: MOD:01714 ! iTRAQ8plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01556
@@ -28181,10 +28184,10 @@ property_value: DiffMono "304.205359" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:730
-is_a: MOD:01428
-is_a: MOD:01429
-is_a: MOD:01526
-is_a: MOD:01591
+is_a: MOD:01428 ! (13)C isotope tagged reagent
+is_a: MOD:01429 ! (15)N isotope tagged reagent
+is_a: MOD:01526 ! iTRAQ8plex reporter+balance reagent acylated residue
+is_a: MOD:01591 ! modifications with monoisotopic mass differences that are nominally equal at 304.205359 Da
 
 [Term]
 id: MOD:01557
@@ -28204,8 +28207,8 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:730
-is_a: MOD:01556
-is_a: MOD:01712
+is_a: MOD:01556 ! iTRAQ8plex-117 reporter+balance reagent acylated residue
+is_a: MOD:01712 ! iTRAQ8plex reporter+balance reagent acylated N-terminal
 
 [Term]
 id: MOD:01558
@@ -28227,9 +28230,9 @@ property_value: MassMono "432.300322" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:730
-is_a: MOD:01556
-is_a: MOD:01710
-is_a: MOD:01875
+is_a: MOD:01556 ! iTRAQ8plex-117 reporter+balance reagent acylated residue
+is_a: MOD:01710 ! iTRAQ8plex reporter+balance reagent N-acylated residue
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01559
@@ -28250,9 +28253,9 @@ property_value: MassMono "467.268688" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:730
-is_a: MOD:00919
-is_a: MOD:01556
-is_a: MOD:01714
+is_a: MOD:00919 ! modified L-tyrosine residue
+is_a: MOD:01556 ! iTRAQ8plex-117 reporter+balance reagent acylated residue
+is_a: MOD:01714 ! iTRAQ8plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01560
@@ -28268,9 +28271,9 @@ property_value: MassAvg "441.26" xsd:float
 property_value: MassMono "441.264271" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00909
-is_a: MOD:01556
-is_a: MOD:01710
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:01556 ! iTRAQ8plex-117 reporter+balance reagent acylated residue
+is_a: MOD:01710 ! iTRAQ8plex reporter+balance reagent N-acylated residue
 
 [Term]
 id: MOD:01561
@@ -28286,9 +28289,9 @@ property_value: MassAvg "391.24" xsd:float
 property_value: MassMono "391.237388" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02003
-is_a: MOD:01556
-is_a: MOD:01714
+is_a: MOD:02003 ! O3-acylated L-serine
+is_a: MOD:01556 ! iTRAQ8plex-117 reporter+balance reagent acylated residue
+is_a: MOD:01714 ! iTRAQ8plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01562
@@ -28304,9 +28307,9 @@ property_value: MassAvg "405.25" xsd:float
 property_value: MassMono "405.253038" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02004
-is_a: MOD:01556
-is_a: MOD:01714
+is_a: MOD:02004 ! O3-acylated L-threonine
+is_a: MOD:01556 ! iTRAQ8plex-117 reporter+balance reagent acylated residue
+is_a: MOD:01714 ! iTRAQ8plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01563
@@ -28324,10 +28327,10 @@ property_value: DiffMono "304.199039" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:731
-is_a: MOD:01428
-is_a: MOD:01429
-is_a: MOD:01526
-is_a: MOD:01584
+is_a: MOD:01428 ! (13)C isotope tagged reagent
+is_a: MOD:01429 ! (15)N isotope tagged reagent
+is_a: MOD:01526 ! iTRAQ8plex reporter+balance reagent acylated residue
+is_a: MOD:01584 ! modifications with monoisotopic mass differences that are nominally equal at 304.199039 Da
 
 [Term]
 id: MOD:01564
@@ -28346,8 +28349,8 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:731
-is_a: MOD:01563
-is_a: MOD:01712
+is_a: MOD:01563 ! iTRAQ8plex-118 reporter+balance reagent acylated residue
+is_a: MOD:01712 ! iTRAQ8plex reporter+balance reagent acylated N-terminal
 
 [Term]
 id: MOD:01565
@@ -28368,9 +28371,9 @@ property_value: MassMono "432.294002" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:731
-is_a: MOD:01563
-is_a: MOD:01710
-is_a: MOD:01875
+is_a: MOD:01563 ! iTRAQ8plex-118 reporter+balance reagent acylated residue
+is_a: MOD:01710 ! iTRAQ8plex reporter+balance reagent N-acylated residue
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01566
@@ -28390,9 +28393,9 @@ property_value: MassMono "467.262368" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:731
-is_a: MOD:00919
-is_a: MOD:01563
-is_a: MOD:01714
+is_a: MOD:00919 ! modified L-tyrosine residue
+is_a: MOD:01563 ! iTRAQ8plex-118 reporter+balance reagent acylated residue
+is_a: MOD:01714 ! iTRAQ8plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01567
@@ -28408,9 +28411,9 @@ property_value: MassAvg "441.26" xsd:float
 property_value: MassMono "441.257951" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00909
-is_a: MOD:01563
-is_a: MOD:01710
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:01563 ! iTRAQ8plex-118 reporter+balance reagent acylated residue
+is_a: MOD:01710 ! iTRAQ8plex reporter+balance reagent N-acylated residue
 
 [Term]
 id: MOD:01568
@@ -28426,9 +28429,9 @@ property_value: MassAvg "391.23" xsd:float
 property_value: MassMono "391.231068" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02003
-is_a: MOD:01563
-is_a: MOD:01714
+is_a: MOD:02003 ! O3-acylated L-serine
+is_a: MOD:01563 ! iTRAQ8plex-118 reporter+balance reagent acylated residue
+is_a: MOD:01714 ! iTRAQ8plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01569
@@ -28444,9 +28447,9 @@ property_value: MassAvg "405.25" xsd:float
 property_value: MassMono "405.246718" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02004
-is_a: MOD:01563
-is_a: MOD:01714
+is_a: MOD:02004 ! O3-acylated L-threonine
+is_a: MOD:01563 ! iTRAQ8plex-118 reporter+balance reagent acylated residue
+is_a: MOD:01714 ! iTRAQ8plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01570
@@ -28464,10 +28467,10 @@ property_value: DiffMono "304.199039" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:731
-is_a: MOD:01428
-is_a: MOD:01429
-is_a: MOD:01526
-is_a: MOD:01584
+is_a: MOD:01428 ! (13)C isotope tagged reagent
+is_a: MOD:01429 ! (15)N isotope tagged reagent
+is_a: MOD:01526 ! iTRAQ8plex reporter+balance reagent acylated residue
+is_a: MOD:01584 ! modifications with monoisotopic mass differences that are nominally equal at 304.199039 Da
 
 [Term]
 id: MOD:01571
@@ -28486,8 +28489,8 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:731
-is_a: MOD:01570
-is_a: MOD:01712
+is_a: MOD:01570 ! iTRAQ8plex-119 reporter+balance reagent acylated residue
+is_a: MOD:01712 ! iTRAQ8plex reporter+balance reagent acylated N-terminal
 
 [Term]
 id: MOD:01572
@@ -28508,9 +28511,9 @@ property_value: MassMono "432.294002" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:731
-is_a: MOD:01570
-is_a: MOD:01710
-is_a: MOD:01875
+is_a: MOD:01570 ! iTRAQ8plex-119 reporter+balance reagent acylated residue
+is_a: MOD:01710 ! iTRAQ8plex reporter+balance reagent N-acylated residue
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01573
@@ -28530,9 +28533,9 @@ property_value: MassMono "467.262368" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:731
-is_a: MOD:00919
-is_a: MOD:01570
-is_a: MOD:01714
+is_a: MOD:00919 ! modified L-tyrosine residue
+is_a: MOD:01570 ! iTRAQ8plex-119 reporter+balance reagent acylated residue
+is_a: MOD:01714 ! iTRAQ8plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01574
@@ -28548,9 +28551,9 @@ property_value: MassAvg "441.26" xsd:float
 property_value: MassMono "441.257951" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00909
-is_a: MOD:01570
-is_a: MOD:01710
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:01570 ! iTRAQ8plex-119 reporter+balance reagent acylated residue
+is_a: MOD:01710 ! iTRAQ8plex reporter+balance reagent N-acylated residue
 
 [Term]
 id: MOD:01575
@@ -28566,9 +28569,9 @@ property_value: MassAvg "391.23" xsd:float
 property_value: MassMono "391.231068" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02003
-is_a: MOD:01570
-is_a: MOD:01714
+is_a: MOD:02003 ! O3-acylated L-serine
+is_a: MOD:01570 ! iTRAQ8plex-119 reporter+balance reagent acylated residue
+is_a: MOD:01714 ! iTRAQ8plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01576
@@ -28584,9 +28587,9 @@ property_value: MassAvg "405.25" xsd:float
 property_value: MassMono "405.246718" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02004
-is_a: MOD:01570
-is_a: MOD:01714
+is_a: MOD:02004 ! O3-acylated L-threonine
+is_a: MOD:01570 ! iTRAQ8plex-119 reporter+balance reagent acylated residue
+is_a: MOD:01714 ! iTRAQ8plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01577
@@ -28604,10 +28607,10 @@ property_value: DiffMono "304.199039" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:731
-is_a: MOD:01428
-is_a: MOD:01429
-is_a: MOD:01526
-is_a: MOD:01584
+is_a: MOD:01428 ! (13)C isotope tagged reagent
+is_a: MOD:01429 ! (15)N isotope tagged reagent
+is_a: MOD:01526 ! iTRAQ8plex reporter+balance reagent acylated residue
+is_a: MOD:01584 ! modifications with monoisotopic mass differences that are nominally equal at 304.199039 Da
 
 [Term]
 id: MOD:01578
@@ -28626,8 +28629,8 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:731
-is_a: MOD:01577
-is_a: MOD:01712
+is_a: MOD:01577 ! iTRAQ8plex-121 reporter+balance reagent acylated residue
+is_a: MOD:01712 ! iTRAQ8plex reporter+balance reagent acylated N-terminal
 
 [Term]
 id: MOD:01579
@@ -28648,9 +28651,9 @@ property_value: MassMono "432.294002" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:731
-is_a: MOD:01577
-is_a: MOD:01710
-is_a: MOD:01875
+is_a: MOD:01577 ! iTRAQ8plex-121 reporter+balance reagent acylated residue
+is_a: MOD:01710 ! iTRAQ8plex reporter+balance reagent N-acylated residue
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01580
@@ -28670,9 +28673,9 @@ property_value: MassMono "467.262368" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:731
-is_a: MOD:00919
-is_a: MOD:01577
-is_a: MOD:01714
+is_a: MOD:00919 ! modified L-tyrosine residue
+is_a: MOD:01577 ! iTRAQ8plex-121 reporter+balance reagent acylated residue
+is_a: MOD:01714 ! iTRAQ8plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01581
@@ -28688,9 +28691,9 @@ property_value: MassAvg "441.26" xsd:float
 property_value: MassMono "441.257951" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00909
-is_a: MOD:01577
-is_a: MOD:01710
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:01577 ! iTRAQ8plex-121 reporter+balance reagent acylated residue
+is_a: MOD:01710 ! iTRAQ8plex reporter+balance reagent N-acylated residue
 
 [Term]
 id: MOD:01582
@@ -28706,9 +28709,9 @@ property_value: MassAvg "391.23" xsd:float
 property_value: MassMono "391.231068" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02003
-is_a: MOD:01577
-is_a: MOD:01714
+is_a: MOD:02003 ! O3-acylated L-serine
+is_a: MOD:01577 ! iTRAQ8plex-121 reporter+balance reagent acylated residue
+is_a: MOD:01714 ! iTRAQ8plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01583
@@ -28724,17 +28727,17 @@ property_value: MassAvg "405.25" xsd:float
 property_value: MassMono "405.246718" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02004
-is_a: MOD:01577
-is_a: MOD:01714
+is_a: MOD:02004 ! O3-acylated L-threonine
+is_a: MOD:01577 ! iTRAQ8plex-121 reporter+balance reagent acylated residue
+is_a: MOD:01714 ! iTRAQ8plex reporter+balance reagent O-acylated residue
 
 [Term]
 id: MOD:01584
 name: modifications with monoisotopic mass differences that are nominally equal at 304.199039 Da
 def: "Modifications that have monoisotopic mass differences from their respective origins of 304.199039 Da." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:01515
-is_a: MOD:01592
+is_a: MOD:01515 ! modifications with monoisotopic mass differences that are nominally equal at a resolution below 0.000001 Da
+is_a: MOD:01592 ! modifications with monoisotopic mass differences that are nominally equal at 304.199-304.206 Da
 
 [Term]
 id: MOD:01585
@@ -28757,10 +28760,10 @@ property_value: Origin "G, S" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0422
-is_a: MOD:00885
-is_a: MOD:02047
-is_a: MOD:02055
-is_a: MOD:00954
+is_a: MOD:00885 ! ester crosslinked residues
+is_a: MOD:02047 ! crosslinked glycine residue
+is_a: MOD:02055 ! crosslinked L-serine residue
+is_a: MOD:00954 ! crosslinked residues with loss of water
 
 [Term]
 id: MOD:01586
@@ -28783,10 +28786,10 @@ property_value: Origin "G, T" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0423
-is_a: MOD:00885
-is_a: MOD:02047
-is_a: MOD:00917
-is_a: MOD:00954
+is_a: MOD:00885 ! ester crosslinked residues
+is_a: MOD:02047 ! crosslinked glycine residue
+is_a: MOD:00917 ! modified L-threonine residue
+is_a: MOD:00954 ! crosslinked residues with loss of water
 
 [Term]
 id: MOD:01587
@@ -28808,8 +28811,8 @@ property_value: MassMono "210.040558" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0399
-is_a: MOD:00861
-is_a: MOD:00916
+is_a: MOD:00861 ! phosphorus containing modified residue
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:01588
@@ -28833,8 +28836,8 @@ property_value: MassMono "253.094785" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0400
-is_a: MOD:00861
-is_a: MOD:00916
+is_a: MOD:00861 ! phosphorus containing modified residue
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:01589
@@ -28857,7 +28860,7 @@ property_value: MassMono "331.137950" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0547
-is_a: MOD:00002
+is_a: MOD:00002 ! O-glycosyl-L-serine
 
 [Term]
 id: MOD:01590
@@ -28874,24 +28877,24 @@ property_value: MassAvg "390.57" xsd:float
 property_value: MassMono "390.267114" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00437
-is_a: MOD:00601
-is_a: MOD:01115
+is_a: MOD:00437 ! farnesylated residue
+is_a: MOD:00601 ! cyclized residue
+is_a: MOD:01115 ! isoprenylated tryptophan
 
 [Term]
 id: MOD:01591
 name: modifications with monoisotopic mass differences that are nominally equal at 304.205359 Da
 def: "Modifications that have monoisotopic mass differences from their respective origins of 304.205359 Da." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:01515
-is_a: MOD:01592
+is_a: MOD:01515 ! modifications with monoisotopic mass differences that are nominally equal at a resolution below 0.000001 Da
+is_a: MOD:01592 ! modifications with monoisotopic mass differences that are nominally equal at 304.199-304.206 Da
 
 [Term]
 id: MOD:01592
 name: modifications with monoisotopic mass differences that are nominally equal at 304.199-304.206 Da
 def: "Modifications that have monoisotopic mass differences from their respective origins of 304.199-304.206 Da." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:01514
+is_a: MOD:01514 ! modifications with monoisotopic mass differences that are nominally equal at a resolution below 0.01 Da
 
 [Term]
 id: MOD:01593
@@ -28899,7 +28902,7 @@ name: iTRAQ8plex reporter fragment
 def: "A protein modification reporter fragment produced by an Applied Biosystems iTRAQ8plex reagent derivatized residue." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "4-methyl-1-methylidenepiperazin-1-ium" EXACT PSI-MOD-alternate []
-is_a: MOD:01520
+is_a: MOD:01520 ! modification reporter fragment
 
 [Term]
 id: MOD:01594
@@ -28913,8 +28916,8 @@ property_value: MassAvg "113.11" xsd:float
 property_value: MassMono "113.107325" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01593
-relationship: derives_from MOD:01528
+is_a: MOD:01593 ! iTRAQ8plex reporter fragment
+relationship: derives_from MOD:01528 ! iTRAQ8plex-113 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01595
@@ -28928,8 +28931,8 @@ property_value: MassAvg "114.11" xsd:float
 property_value: MassMono "114.110680" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01593
-relationship: derives_from MOD:01535
+is_a: MOD:01593 ! iTRAQ8plex reporter fragment
+relationship: derives_from MOD:01535 ! iTRAQ8plex-114 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01596
@@ -28943,8 +28946,8 @@ property_value: MassAvg "115.11" xsd:float
 property_value: MassMono "115.107715" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01593
-relationship: derives_from MOD:01542
+is_a: MOD:01593 ! iTRAQ8plex reporter fragment
+relationship: derives_from MOD:01542 ! iTRAQ8plex-115 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01597
@@ -28958,8 +28961,8 @@ property_value: MassAvg "116.11" xsd:float
 property_value: MassMono "116.111069" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01593
-relationship: derives_from MOD:01549
+is_a: MOD:01593 ! iTRAQ8plex reporter fragment
+relationship: derives_from MOD:01549 ! iTRAQ8plex-116 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01598
@@ -28973,8 +28976,8 @@ property_value: MassAvg "117.11" xsd:float
 property_value: MassMono "117.114424" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01593
-relationship: derives_from MOD:01556
+is_a: MOD:01593 ! iTRAQ8plex reporter fragment
+relationship: derives_from MOD:01556 ! iTRAQ8plex-117 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01599
@@ -28988,8 +28991,8 @@ property_value: MassAvg "118.11" xsd:float
 property_value: MassMono "118.111459" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01593
-relationship: derives_from MOD:01563
+is_a: MOD:01593 ! iTRAQ8plex reporter fragment
+relationship: derives_from MOD:01563 ! iTRAQ8plex-118 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01600
@@ -29003,8 +29006,8 @@ property_value: MassAvg "119.11" xsd:float
 property_value: MassMono "119.114814" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01593
-relationship: derives_from MOD:01570
+is_a: MOD:01593 ! iTRAQ8plex reporter fragment
+relationship: derives_from MOD:01570 ! iTRAQ8plex-119 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01601
@@ -29018,8 +29021,8 @@ property_value: MassAvg "121.12" xsd:float
 property_value: MassMono "121.121524" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01593
-relationship: derives_from MOD:01577
+is_a: MOD:01593 ! iTRAQ8plex reporter fragment
+relationship: derives_from MOD:01577 ! iTRAQ8plex-121 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01602
@@ -29039,8 +29042,8 @@ property_value: MassMono "257.119798" xsd:float
 property_value: Origin "K, M" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0401
-is_a: MOD:02051
-is_a: MOD:02052
+is_a: MOD:02051 ! crosslinked L-lysine residue
+is_a: MOD:02052 ! crosslinked L-methionine residue
 
 [Term]
 id: MOD:01603
@@ -29056,8 +29059,8 @@ property_value: MassMono "130.089033" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:995
-is_a: MOD:00843
-is_a: MOD:00912
+is_a: MOD:00843 ! (15)N labeled residue
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:01604
@@ -29072,8 +29075,8 @@ property_value: MassAvg "160.09" xsd:float
 property_value: MassMono "160.089251" xsd:float
 property_value: Origin "R" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00843
-is_a: MOD:00902
+is_a: MOD:00843 ! (15)N labeled residue
+is_a: MOD:00902 ! modified L-arginine residue
 
 [Term]
 id: MOD:01605
@@ -29093,7 +29096,7 @@ property_value: MassMono "272.100836" xsd:float
 property_value: Origin "E" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0406
-is_a: MOD:00906
+is_a: MOD:00906 ! modified L-glutamic acid residue
 
 [Term]
 id: MOD:01606
@@ -29109,8 +29112,8 @@ property_value: MassAvg "352.24" xsd:float
 property_value: MassMono "352.067167" xsd:float
 property_value: Origin "E" xsd:string
 property_value: Source "hypothetical" xsd:string
-is_a: MOD:00861
-is_a: MOD:00906
+is_a: MOD:00861 ! phosphorus containing modified residue
+is_a: MOD:00906 ! modified L-glutamic acid residue
 
 [Term]
 id: MOD:01607
@@ -29130,7 +29133,7 @@ property_value: MassAvg "256.26" xsd:float
 property_value: MassMono "256.105922" xsd:float
 property_value: Origin "E" xsd:string
 property_value: Source "hypothetical" xsd:string
-is_a: MOD:00906
+is_a: MOD:00906 ! modified L-glutamic acid residue
 
 [Term]
 id: MOD:01608
@@ -29152,7 +29155,7 @@ property_value: MassMono "257.137556" xsd:float
 property_value: Origin "E" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0407
-is_a: MOD:00906
+is_a: MOD:00906 ! modified L-glutamic acid residue
 
 [Term]
 id: MOD:01609
@@ -29170,9 +29173,9 @@ property_value: MassMono "364.127051" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0504
-is_a: MOD:00918
-relationship: has_functional_parent MOD:00222
-relationship: has_functional_parent MOD:01664
+is_a: MOD:00918 ! modified L-tryptophan residue
+relationship: has_functional_parent MOD:00222 ! 2'-alpha-mannosyl-L-tryptophan
+relationship: has_functional_parent MOD:01664 ! 7'-hydroxy-L-tryptophan
 
 [Term]
 id: MOD:01610
@@ -29192,8 +29195,8 @@ property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0412
-is_a: MOD:01689
-is_a: MOD:01803
+is_a: MOD:01689 ! alpha-carboxyl methylated residue
+is_a: MOD:01803 ! O-methylated threonine
 
 [Term]
 id: MOD:01611
@@ -29217,9 +29220,9 @@ property_value: MassAvg "692.60" xsd:float
 property_value: MassMono "692.141411" xsd:float
 property_value: Origin "C, H" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:02044
-is_a: MOD:02048
-is_a: MOD:01621
+is_a: MOD:02044 ! crosslinked L-cysteine residue
+is_a: MOD:02048 ! crosslinked L-histidine residue
+is_a: MOD:01621 ! flavin crosslinked residues
 
 [Term]
 id: MOD:01612
@@ -29242,7 +29245,7 @@ property_value: MassMono "288.959976" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0411
-is_a: MOD:01228
+is_a: MOD:01228 ! monoiodinated tyrosine
 
 [Term]
 id: MOD:01613
@@ -29265,7 +29268,7 @@ property_value: MassMono "414.856624" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0408
-is_a: MOD:01140
+is_a: MOD:01140 ! diiodinated tyrosine
 
 [Term]
 id: MOD:01614
@@ -29291,8 +29294,8 @@ property_value: Origin "G" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0409
-is_a: MOD:00908
-is_a: MOD:01165
+is_a: MOD:00908 ! modified glycine residue
+is_a: MOD:01165 ! adenylated residue
 
 [Term]
 id: MOD:01615
@@ -29315,9 +29318,9 @@ property_value: Origin "C, G" xsd:string
 property_value: Source "hypothetical" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0410
-is_a: MOD:00395
-is_a: MOD:02047
-is_a: MOD:00954
+is_a: MOD:00395 ! thioester crosslinked residues
+is_a: MOD:02047 ! crosslinked glycine residue
+is_a: MOD:00954 ! crosslinked residues with loss of water
 
 [Term]
 id: MOD:01616
@@ -29337,7 +29340,7 @@ property_value: MassMono "299.918933" xsd:float
 property_value: Origin "C, C" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0417
-is_a: MOD:01620
+is_a: MOD:01620 ! polysulfide crosslinked residues
 
 [Term]
 id: MOD:01617
@@ -29356,8 +29359,8 @@ property_value: MassMono "343.066832" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0596
-is_a: MOD:00005
-is_a: MOD:01804
+is_a: MOD:00005 ! O-glycosyl-L-threonine
+is_a: MOD:01804 ! glycosylphosphorylated residue
 
 [Term]
 id: MOD:01618
@@ -29378,33 +29381,33 @@ property_value: Origin "A, N" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0418
-is_a: MOD:00688
-is_a: MOD:02040
-is_a: MOD:02042
-is_a: MOD:00946
+is_a: MOD:00688 ! isopeptide crosslinked residues
+is_a: MOD:02040 ! crosslinked L-alanine residue
+is_a: MOD:02042 ! crosslinked L-asparagine residue
+is_a: MOD:00946 ! crosslinked residues with loss of ammonia
 
 [Term]
 id: MOD:01619
 name: multisulfide crosslinked residues
 def: "A protein modification that crosslinks two cysteine residues by formation of a chain of two or more bonded sulfur atoms." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00033
-is_a: MOD:02044
+is_a: MOD:00033 ! crosslinked residues
+is_a: MOD:02044 ! crosslinked L-cysteine residue
 
 [Term]
 id: MOD:01620
 name: polysulfide crosslinked residues
 def: "A protein modification that crosslinks two cysteine residues by formation of a chain of three or more bonded sulfur atoms." [PubMed:18688235]
-is_a: MOD:00860
-is_a: MOD:01619
+is_a: MOD:00860 ! sulfur containing modified residue
+is_a: MOD:01619 ! multisulfide crosslinked residues
 
 [Term]
 id: MOD:01621
 name: flavin crosslinked residues
 def: "A protein modification that crosslinks two or more amino acid residues by forming an adduct with a compound containing a flavin group." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00033
-is_a: MOD:00697
+is_a: MOD:00033 ! crosslinked residues
+is_a: MOD:00697 ! flavin modified residue
 
 [Term]
 id: MOD:01622
@@ -29421,8 +29424,8 @@ property_value: MassMono "202.074228" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:35
-is_a: MOD:00425
-is_a: MOD:00918
+is_a: MOD:00425 ! monohydroxylated residue
+is_a: MOD:00918 ! modified L-tryptophan residue
 
 [Term]
 id: MOD:01623
@@ -29438,7 +29441,7 @@ property_value: MassMono "72.998620" xsd:float
 property_value: Origin "G" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
-is_a: MOD:01625
+is_a: MOD:01625 ! 1-thioglycine
 
 [Term]
 id: MOD:01624
@@ -29462,9 +29465,9 @@ property_value: MassMono "154.037842" xsd:float
 property_value: Origin "G, N" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: uniprot.ptm:PTM-0450
-is_a: MOD:02042
-is_a: MOD:00946
-is_a: MOD:01628
+is_a: MOD:02042 ! crosslinked L-asparagine residue
+is_a: MOD:00946 ! crosslinked residues with loss of ammonia
+is_a: MOD:01628 ! (2-aminosuccinimidyl)acetic acid
 
 [Term]
 id: MOD:01625
@@ -29485,8 +29488,8 @@ property_value: DiffFormula "C 0 H 0 N 0 O -1 S 1" xsd:string
 property_value: DiffMono "15.977156" xsd:float
 property_value: Origin "G" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00749
-is_a: MOD:00908
+is_a: MOD:00749 ! sulfur substitution for oxygen
+is_a: MOD:00908 ! modified glycine residue
 
 [Term]
 id: MOD:01626
@@ -29512,7 +29515,7 @@ property_value: DiffAvg "-2.02" xsd:float
 property_value: DiffFormula "C 0 H -2 N 0 O 0 S 0" xsd:string
 property_value: DiffMono "-2.015650" xsd:float
 property_value: Source "natural" xsd:string
-is_a: MOD:00905
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:01627
@@ -29525,9 +29528,9 @@ property_value: MassAvg "251.17" xsd:float
 property_value: MassMono "251.947170" xsd:float
 property_value: Origin "C, X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00692
-is_a: MOD:00859
-is_a: MOD:02044
+is_a: MOD:00692 ! uncategorized crosslinked residues
+is_a: MOD:00859 ! modified residue that can arise from different natural residues
+is_a: MOD:02044 ! crosslinked L-cysteine residue
 
 [Term]
 id: MOD:01628
@@ -29540,8 +29543,8 @@ property_value: MassAvg "154.13" xsd:float
 property_value: MassMono "154.037842" xsd:float
 property_value: Origin "G, X" xsd:string
 property_value: Source "hypothetical" xsd:string
-is_a: MOD:02047
-is_a: MOD:01944
+is_a: MOD:02047 ! crosslinked glycine residue
+is_a: MOD:01944 ! 2-aminosuccinimide ring crosslinked residues
 
 [Term]
 id: MOD:01629
@@ -29557,8 +29560,8 @@ property_value: MassMono "286.086152" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
-is_a: MOD:00859
-is_a: MOD:02044
+is_a: MOD:00859 ! modified residue that can arise from different natural residues
+is_a: MOD:02044 ! crosslinked L-cysteine residue
 
 [Term]
 id: MOD:01630
@@ -29578,10 +29581,10 @@ property_value: MassMono "239.126991" xsd:float
 property_value: Origin "K, X" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0397
-is_a: MOD:02051
-is_a: MOD:01875
-is_a: MOD:00688
-is_a: MOD:00859
+is_a: MOD:02051 ! crosslinked L-lysine residue
+is_a: MOD:01875 ! N6-acylated L-lysine
+is_a: MOD:00688 ! isopeptide crosslinked residues
+is_a: MOD:00859 ! modified residue that can arise from different natural residues
 
 [Term]
 id: MOD:01631
@@ -29594,8 +29597,8 @@ property_value: DiffFormula "C -3 H -5 N -1 O -1" xsd:string
 property_value: DiffMono "-71.037114" xsd:float
 property_value: Origin "A" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00901
-is_a: MOD:01651
+is_a: MOD:00901 ! modified L-alanine residue
+is_a: MOD:01651 ! natural, standard, encoded residue removal
 
 [Term]
 id: MOD:01632
@@ -29608,8 +29611,8 @@ property_value: DiffFormula "C -6 H -12 N -4 O -1" xsd:string
 property_value: DiffMono "-156.101111" xsd:float
 property_value: Origin "R" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00902
-is_a: MOD:01651
+is_a: MOD:00902 ! modified L-arginine residue
+is_a: MOD:01651 ! natural, standard, encoded residue removal
 
 [Term]
 id: MOD:01633
@@ -29622,8 +29625,8 @@ property_value: DiffFormula "C -4 H -6 N -2 O -2" xsd:string
 property_value: DiffMono "-114.042927" xsd:float
 property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00903
-is_a: MOD:01651
+is_a: MOD:00903 ! modified L-asparagine residue
+is_a: MOD:01651 ! natural, standard, encoded residue removal
 
 [Term]
 id: MOD:01634
@@ -29636,8 +29639,8 @@ property_value: DiffFormula "C -4 H -5 N -1 O -3" xsd:string
 property_value: DiffMono "-115.026943" xsd:float
 property_value: Origin "D" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00904
-is_a: MOD:01651
+is_a: MOD:00904 ! modified L-aspartic acid residue
+is_a: MOD:01651 ! natural, standard, encoded residue removal
 
 [Term]
 id: MOD:01635
@@ -29650,8 +29653,8 @@ property_value: DiffFormula "C -3 H -5 N -1 O -1 S -1" xsd:string
 property_value: DiffMono "-103.009185" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00905
-is_a: MOD:01651
+is_a: MOD:00905 ! modified L-cysteine residue
+is_a: MOD:01651 ! natural, standard, encoded residue removal
 
 [Term]
 id: MOD:01636
@@ -29664,8 +29667,8 @@ property_value: DiffFormula "C -5 H -7 N -1 O -3" xsd:string
 property_value: DiffMono "-129.042593" xsd:float
 property_value: Origin "E" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00906
-is_a: MOD:01651
+is_a: MOD:00906 ! modified L-glutamic acid residue
+is_a: MOD:01651 ! natural, standard, encoded residue removal
 
 [Term]
 id: MOD:01637
@@ -29678,8 +29681,8 @@ property_value: DiffFormula "C -5 H -8 N -2 O -2" xsd:string
 property_value: DiffMono "-128.058578" xsd:float
 property_value: Origin "Q" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00907
-is_a: MOD:01651
+is_a: MOD:00907 ! modified L-glutamine residue
+is_a: MOD:01651 ! natural, standard, encoded residue removal
 
 [Term]
 id: MOD:01638
@@ -29692,8 +29695,8 @@ property_value: DiffFormula "C -2 H -3 N -1 O -1" xsd:string
 property_value: DiffMono "-57.021464" xsd:float
 property_value: Origin "G" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00908
-is_a: MOD:01651
+is_a: MOD:00908 ! modified glycine residue
+is_a: MOD:01651 ! natural, standard, encoded residue removal
 
 [Term]
 id: MOD:01639
@@ -29706,8 +29709,8 @@ property_value: DiffFormula "C -6 H -7 N -3 O -1" xsd:string
 property_value: DiffMono "-137.058912" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00909
-is_a: MOD:01651
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:01651 ! natural, standard, encoded residue removal
 
 [Term]
 id: MOD:01640
@@ -29720,8 +29723,8 @@ property_value: DiffFormula "C -6 H -11 N -1 O -1" xsd:string
 property_value: DiffMono "-113.084064" xsd:float
 property_value: Origin "I" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00910
-is_a: MOD:01651
+is_a: MOD:00910 ! modified L-isoleucine residue
+is_a: MOD:01651 ! natural, standard, encoded residue removal
 
 [Term]
 id: MOD:01641
@@ -29734,8 +29737,8 @@ property_value: DiffFormula "C -6 H -11 N -1 O -1" xsd:string
 property_value: DiffMono "-113.084064" xsd:float
 property_value: Origin "L" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00911
-is_a: MOD:01651
+is_a: MOD:00911 ! modified L-leucine residue
+is_a: MOD:01651 ! natural, standard, encoded residue removal
 
 [Term]
 id: MOD:01642
@@ -29748,8 +29751,8 @@ property_value: DiffFormula "C -6 H -12 N -2 O -1" xsd:string
 property_value: DiffMono "-128.094963" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00912
-is_a: MOD:01651
+is_a: MOD:00912 ! modified L-lysine residue
+is_a: MOD:01651 ! natural, standard, encoded residue removal
 
 [Term]
 id: MOD:01643
@@ -29765,8 +29768,8 @@ property_value: DiffMono "-131.040485" xsd:float
 property_value: Origin "M" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:765
-is_a: MOD:00913
-is_a: MOD:01651
+is_a: MOD:00913 ! modified L-methionine residue
+is_a: MOD:01651 ! natural, standard, encoded residue removal
 
 [Term]
 id: MOD:01644
@@ -29779,8 +29782,8 @@ property_value: DiffFormula "C -9 H -9 N -1 O -1" xsd:string
 property_value: DiffMono "-147.068414" xsd:float
 property_value: Origin "F" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00914
-is_a: MOD:01651
+is_a: MOD:00914 ! modified L-phenylalanine residue
+is_a: MOD:01651 ! natural, standard, encoded residue removal
 
 [Term]
 id: MOD:01645
@@ -29793,8 +29796,8 @@ property_value: DiffFormula "C -5 H -7 N -1 O -1" xsd:string
 property_value: DiffMono "-97.052764" xsd:float
 property_value: Origin "P" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00915
-is_a: MOD:01651
+is_a: MOD:00915 ! modified L-proline residue
+is_a: MOD:01651 ! natural, standard, encoded residue removal
 
 [Term]
 id: MOD:01646
@@ -29807,8 +29810,8 @@ property_value: DiffFormula "C -3 H -5 N -1 O -2" xsd:string
 property_value: DiffMono "-87.032028" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00916
-is_a: MOD:01651
+is_a: MOD:00916 ! modified L-serine residue
+is_a: MOD:01651 ! natural, standard, encoded residue removal
 
 [Term]
 id: MOD:01647
@@ -29821,8 +29824,8 @@ property_value: DiffFormula "C -4 H -7 N -1 O -2" xsd:string
 property_value: DiffMono "-101.047678" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00917
-is_a: MOD:01651
+is_a: MOD:00917 ! modified L-threonine residue
+is_a: MOD:01651 ! natural, standard, encoded residue removal
 
 [Term]
 id: MOD:01648
@@ -29835,8 +29838,8 @@ property_value: DiffFormula "C -11 H -10 N -2 O -1" xsd:string
 property_value: DiffMono "-186.079313" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00918
-is_a: MOD:01651
+is_a: MOD:00918 ! modified L-tryptophan residue
+is_a: MOD:01651 ! natural, standard, encoded residue removal
 
 [Term]
 id: MOD:01649
@@ -29849,8 +29852,8 @@ property_value: DiffFormula "C -9 H -9 N -1 O -2" xsd:string
 property_value: DiffMono "-163.063329" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00919
-is_a: MOD:01651
+is_a: MOD:00919 ! modified L-tyrosine residue
+is_a: MOD:01651 ! natural, standard, encoded residue removal
 
 [Term]
 id: MOD:01650
@@ -29863,8 +29866,8 @@ property_value: DiffFormula "C -5 H -9 N -1 O -1" xsd:string
 property_value: DiffMono "-99.068414" xsd:float
 property_value: Origin "V" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00920
-is_a: MOD:01651
+is_a: MOD:00920 ! modified L-valine residue
+is_a: MOD:01651 ! natural, standard, encoded residue removal
 
 [Term]
 id: MOD:01651
@@ -29874,8 +29877,8 @@ comment: This represents the loss of an encoded residue in a polypeptide.
 subset: PSI-MOD-slim
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00009
-is_a: MOD:01156
+is_a: MOD:00009 ! natural residue
+is_a: MOD:01156 ! protein modification characterized by chemical process
 
 [Term]
 id: MOD:01652
@@ -29884,7 +29887,7 @@ def: "A protein modification that is produced by formation of an adduct with a s
 comment: These reagents typically react with N6-amino group of lysine residues and a free alpha-amino group of a peptide.
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01653
@@ -29900,7 +29903,7 @@ property_value: DiffMono "233.051050" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:139
-is_a: MOD:01652
+is_a: MOD:01652 ! sulfonyl halide reagent derivatized residue
 
 [Term]
 id: MOD:01654
@@ -29918,8 +29921,8 @@ property_value: MassMono "361.146013" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:139
-is_a: MOD:00912
-is_a: MOD:01653
+is_a: MOD:00912 ! modified L-lysine residue
+is_a: MOD:01653 ! dansyl chloride derivatized residue
 
 [Term]
 id: MOD:01655
@@ -29934,7 +29937,7 @@ property_value: DiffMono "233.051050" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:139
-is_a: MOD:01653
+is_a: MOD:01653 ! dansyl chloride derivatized residue
 
 [Term]
 id: MOD:01656
@@ -29947,7 +29950,7 @@ property_value: DiffFormula "C 14 H 13 N 3 O 2 S 1" xsd:string
 property_value: DiffMono "287.072848" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01652
+is_a: MOD:01652 ! sulfonyl halide reagent derivatized residue
 
 [Term]
 id: MOD:01657
@@ -29963,8 +29966,8 @@ property_value: MassAvg "415.51" xsd:float
 property_value: MassMono "415.167811" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00912
-is_a: MOD:01656
+is_a: MOD:00912 ! modified L-lysine residue
+is_a: MOD:01656 ! Dabsyl chloride derivatized residue
 
 [Term]
 id: MOD:01658
@@ -29977,7 +29980,7 @@ property_value: DiffMono "287.072848" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:01656
+is_a: MOD:01656 ! Dabsyl chloride derivatized residue
 
 [Term]
 id: MOD:01659
@@ -29993,7 +29996,7 @@ property_value: DiffFormula "C 22 H 16 N 2 O 7 S 2" xsd:string
 property_value: DiffMono "484.039893" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01660
@@ -30012,8 +30015,8 @@ property_value: MassAvg "587.64" xsd:float
 property_value: MassMono "587.049078" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00905
-is_a: MOD:01659
+is_a: MOD:00905 ! modified L-cysteine residue
+is_a: MOD:01659 ! Uniblue A derivatized residue
 
 [Term]
 id: MOD:01661
@@ -30032,8 +30035,8 @@ property_value: Origin "Y" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0662
-is_a: MOD:00919
-is_a: MOD:01154
+is_a: MOD:00919 ! modified L-tyrosine residue
+is_a: MOD:01154 ! pyruvic acid
 
 [Term]
 id: MOD:01662
@@ -30051,8 +30054,8 @@ property_value: MassAvg "669.43" xsd:float
 property_value: MassMono "669.119687" xsd:float
 property_value: Origin "Q" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00752
-is_a: MOD:00907
+is_a: MOD:00752 ! adenosine diphosphoribosyl (ADP-ribosyl) modified residue
+is_a: MOD:00907 ! modified L-glutamine residue
 
 [Term]
 id: MOD:01663
@@ -30071,8 +30074,8 @@ property_value: MassAvg "642.41" xsd:float
 property_value: MassMono "642.108787" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00752
-is_a: MOD:00917
+is_a: MOD:00752 ! adenosine diphosphoribosyl (ADP-ribosyl) modified residue
+is_a: MOD:00917 ! modified L-threonine residue
 
 [Term]
 id: MOD:01664
@@ -30090,7 +30093,7 @@ property_value: MassMono "202.074228" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0427
-is_a: MOD:01622
+is_a: MOD:01622 ! monohydroxylated tryptophan
 
 [Term]
 id: MOD:01665
@@ -30103,8 +30106,8 @@ synonym: "N-(DNA-1',2'-dideoxyribos-1'-ylidene)-L-valine" EXACT RESID-name []
 property_value: Origin "V" xsd:string
 property_value: Source "hypothetical" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00750
-is_a: MOD:00920
+is_a: MOD:00750 ! deoxyribonucleic acid linked residue
+is_a: MOD:00920 ! modified L-valine residue
 
 [Term]
 id: MOD:01666
@@ -30119,7 +30122,7 @@ property_value: DiffFormula "C 23 H 22 O 7" xsd:string
 property_value: DiffMono "410.136553" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01667
@@ -30137,8 +30140,8 @@ property_value: MassAvg "538.60" xsd:float
 property_value: MassMono "538.231516" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00912
-is_a: MOD:01666
+is_a: MOD:00912 ! modified L-lysine residue
+is_a: MOD:01666 ! epicocconone derivatized residue
 
 [Term]
 id: MOD:01668
@@ -30156,8 +30159,8 @@ property_value: MassAvg "898.63" xsd:float
 property_value: MassMono "898.168428" xsd:float
 property_value: Origin "D" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00895
-is_a: MOD:00904
+is_a: MOD:00895 ! FAD modified residue
+is_a: MOD:00904 ! modified L-aspartic acid residue
 
 [Term]
 id: MOD:01669
@@ -30182,9 +30185,9 @@ property_value: MassMono "198.148061" xsd:float
 property_value: Origin "R" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: Unimod:37
-is_a: MOD:00430
-is_a: MOD:00602
-is_a: MOD:00658
+is_a: MOD:00430 ! trimethylated residue
+is_a: MOD:00602 ! N-methylated residue
+is_a: MOD:00658 ! methylated arginine
 
 [Term]
 id: MOD:01670
@@ -30204,9 +30207,9 @@ property_value: MassAvg "162.62" xsd:float
 property_value: MassMono "162.055991" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "hypothetical" xsd:string
-is_a: MOD:00912
-is_a: MOD:01672
-is_a: MOD:01911
+is_a: MOD:00912 ! modified L-lysine residue
+is_a: MOD:01672 ! halogenated lysine
+is_a: MOD:01911 ! monochlorinated residue
 
 [Term]
 id: MOD:01671
@@ -30227,15 +30230,15 @@ property_value: MassAvg "216.19" xsd:float
 property_value: MassMono "216.074621" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00671
-is_a: MOD:01978
+is_a: MOD:00671 ! O-acylated residue
+is_a: MOD:01978 ! O-(L-isoaspartyl)-L-threonine
 
 [Term]
 id: MOD:01672
 name: halogenated lysine
 def: "A protein modification that effectively substitutes a hydrogen atom of an L-lysine residue with a halogen atom." [PubMed:18688235]
 property_value: Origin "K" xsd:string
-is_a: MOD:00694
+is_a: MOD:00694 ! halogen containing residue
 
 [Term]
 id: MOD:01673
@@ -30250,7 +30253,7 @@ property_value: DiffFormula "C 8 H 13 N 1 O 5" xsd:string
 property_value: DiffMono "203.079373" xsd:float
 property_value: Origin "X" xsd:string
 xref: Unimod:43
-is_a: MOD:00436
+is_a: MOD:00436 ! N-acetylhexosaminylated residue
 
 [Term]
 id: MOD:01674
@@ -30278,8 +30281,8 @@ property_value: MassMono "317.122300" xsd:float
 property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:43
-is_a: MOD:00160
-is_a: MOD:01673
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
+is_a: MOD:01673 ! N-acetylaminohexosylated residue
 
 [Term]
 id: MOD:01675
@@ -30305,8 +30308,8 @@ property_value: MassMono "290.111401" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:43
-is_a: MOD:00002
-is_a: MOD:01673
+is_a: MOD:00002 ! O-glycosyl-L-serine
+is_a: MOD:01673 ! N-acetylaminohexosylated residue
 
 [Term]
 id: MOD:01676
@@ -30330,8 +30333,8 @@ property_value: MassMono "304.127051" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:43
-is_a: MOD:00005
-is_a: MOD:01673
+is_a: MOD:00005 ! O-glycosyl-L-threonine
+is_a: MOD:01673 ! N-acetylaminohexosylated residue
 
 [Term]
 id: MOD:01677
@@ -30354,8 +30357,8 @@ property_value: MassAvg "316.31" xsd:float
 property_value: MassMono "316.127051" xsd:float
 property_value: Origin "P" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00915
-relationship: contains MOD:01673
+is_a: MOD:00915 ! modified L-proline residue
+relationship: contains MOD:01673 ! N-acetylaminohexosylated residue
 
 [Term]
 id: MOD:01678
@@ -30381,8 +30384,8 @@ property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:5
 xref: uniprot.ptm:PTM-0675
-is_a: MOD:00912
-is_a: MOD:00398
+is_a: MOD:00912 ! modified L-lysine residue
+is_a: MOD:00398 ! carbamoylated residue
 
 [Term]
 id: MOD:01679
@@ -30401,7 +30404,7 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:5
-is_a: MOD:00398
+is_a: MOD:00398 ! carbamoylated residue
 
 [Term]
 id: MOD:01680
@@ -30421,8 +30424,8 @@ property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:34
-is_a: MOD:00599
-is_a: MOD:01460
+is_a: MOD:00599 ! monomethylated residue
+is_a: MOD:01460 ! alpha-amino methylated residue
 
 [Term]
 id: MOD:01681
@@ -30441,8 +30444,8 @@ property_value: MassMono "129.042593" xsd:float
 property_value: Origin "D" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:34
-is_a: MOD:00599
-is_a: MOD:00887
+is_a: MOD:00599 ! monomethylated residue
+is_a: MOD:00887 ! methylated aspartic acid
 
 [Term]
 id: MOD:01682
@@ -30462,8 +30465,8 @@ property_value: MassMono "117.024835" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:34
-is_a: MOD:00599
-is_a: MOD:00660
+is_a: MOD:00599 ! monomethylated residue
+is_a: MOD:00660 ! methylated cysteine
 
 [Term]
 id: MOD:01683
@@ -30482,8 +30485,8 @@ property_value: MassAvg "159.21" xsd:float
 property_value: MassMono "159.113353" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00599
-is_a: MOD:00663
+is_a: MOD:00599 ! monomethylated residue
+is_a: MOD:00663 ! methylated lysine
 
 [Term]
 id: MOD:01684
@@ -30504,7 +30507,7 @@ property_value: MassMono "341.238850" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:47
-is_a: MOD:00905
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:01685
@@ -30521,8 +30524,8 @@ property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:47
-is_a: MOD:00651
-is_a: MOD:01696
+is_a: MOD:00651 ! N-palmitoylated residue
+is_a: MOD:01696 ! alpha-amino acylated residue
 
 [Term]
 id: MOD:01686
@@ -30539,8 +30542,8 @@ property_value: DiffMono "28.031300" xsd:float
 property_value: Origin "X" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:36
-is_a: MOD:00429
-is_a: MOD:01460
+is_a: MOD:00429 ! dimethylated residue
+is_a: MOD:01460 ! alpha-amino methylated residue
 
 [Term]
 id: MOD:01687
@@ -30560,9 +30563,9 @@ property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:37
-is_a: MOD:00430
-is_a: MOD:01460
-relationship: derives_from MOD:01700
+is_a: MOD:00430 ! trimethylated residue
+is_a: MOD:01460 ! alpha-amino methylated residue
+relationship: derives_from MOD:01700 ! alpha-amino protonated residue
 
 [Term]
 id: MOD:01688
@@ -30582,8 +30585,8 @@ property_value: MassMono "130.037842" xsd:float
 property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:35
-is_a: MOD:00425
-is_a: MOD:00903
+is_a: MOD:00425 ! monohydroxylated residue
+is_a: MOD:00903 ! modified L-asparagine residue
 
 [Term]
 id: MOD:01689
@@ -30602,7 +30605,7 @@ property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: Unimod:34
-is_a: MOD:00393
+is_a: MOD:00393 ! O-methylated residue
 
 [Term]
 id: MOD:01690
@@ -30622,8 +30625,8 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0419
-is_a: MOD:00905
-is_a: MOD:01696
+is_a: MOD:00905 ! modified L-cysteine residue
+is_a: MOD:01696 ! alpha-amino acylated residue
 
 [Term]
 id: MOD:01691
@@ -30643,8 +30646,8 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0420
-is_a: MOD:00905
-is_a: MOD:01696
+is_a: MOD:00905 ! modified L-cysteine residue
+is_a: MOD:01696 ! alpha-amino acylated residue
 
 [Term]
 id: MOD:01692
@@ -30662,9 +30665,9 @@ property_value: MassAvg "113.12" xsd:float
 property_value: MassMono "113.047678" xsd:float
 property_value: Origin "E" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00906
-is_a: MOD:01161
-is_a: MOD:01440
+is_a: MOD:00906 ! modified L-glutamic acid residue
+is_a: MOD:01161 ! deoxygenated residue
+is_a: MOD:01440 ! glutamyl semialdehyde
 
 [Term]
 id: MOD:01693
@@ -30681,8 +30684,8 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:25
-is_a: MOD:00418
-is_a: MOD:01696
+is_a: MOD:00418 ! pyridylacetylated residue
+is_a: MOD:01696 ! alpha-amino acylated residue
 
 [Term]
 id: MOD:01694
@@ -30702,7 +30705,7 @@ property_value: MassMono "524.151826" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0428
-is_a: MOD:00905
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:01695
@@ -30717,8 +30720,8 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:293
-is_a: MOD:00612
-is_a: MOD:01696
+is_a: MOD:00612 ! 3-(carboxamidomethylthio)propanoylated residue
+is_a: MOD:01696 ! alpha-amino acylated residue
 
 [Term]
 id: MOD:01696
@@ -30728,7 +30731,7 @@ subset: PSI-MOD-slim
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00670
+is_a: MOD:00670 ! N-acylated residue
 
 [Term]
 id: MOD:01697
@@ -30744,7 +30747,7 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:276
-is_a: MOD:00596
+is_a: MOD:00596 ! 4-(2-aminoethyl)benzenesulfonyl fluoride derivatized residue
 
 [Term]
 id: MOD:01698
@@ -30761,8 +30764,8 @@ property_value: FormalCharge "1+" xsd:string
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00711
-is_a: MOD:01460
+is_a: MOD:00711 ! trimethylated protonated-residue
+is_a: MOD:01460 ! alpha-amino methylated residue
 
 [Term]
 id: MOD:01699
@@ -30776,7 +30779,7 @@ property_value: DiffMono "1.007276" xsd:float
 property_value: FormalCharge "1+" xsd:string
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:01700
@@ -30791,7 +30794,7 @@ property_value: FormalCharge "1+" xsd:string
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:01699
+is_a: MOD:01699 ! protonated residue
 
 [Term]
 id: MOD:01701
@@ -30805,7 +30808,7 @@ property_value: DiffMono "-1.007276" xsd:float
 property_value: FormalCharge "1-" xsd:string
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:01702
@@ -30820,7 +30823,7 @@ property_value: FormalCharge "1-" xsd:string
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
-is_a: MOD:01701
+is_a: MOD:01701 ! deprotonated residue
 
 [Term]
 id: MOD:01703
@@ -30839,7 +30842,7 @@ property_value: Formula "C 4 H 5 N 1 O 1" xsd:string
 property_value: MassAvg "83.09" xsd:float
 property_value: MassMono "83.037114" xsd:float
 property_value: Origin "X" xsd:string
-is_a: MOD:00859
+is_a: MOD:00859 ! modified residue that can arise from different natural residues
 
 [Term]
 id: MOD:01704
@@ -30856,8 +30859,8 @@ property_value: MassAvg "83.09" xsd:float
 property_value: MassMono "83.037114" xsd:float
 property_value: Origin "M" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00913
-is_a: MOD:01703
+is_a: MOD:00913 ! modified L-methionine residue
+is_a: MOD:01703 ! dehydrobutyrine
 
 [Term]
 id: MOD:01705
@@ -30866,7 +30869,7 @@ def: "A protein modification that effectively replaces a residue hydrogen with a
 subset: PSI-MOD-slim
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00649
+is_a: MOD:00649 ! acylated residue
 
 [Term]
 id: MOD:01706
@@ -30875,7 +30878,7 @@ def: "A protein modification that effectively replaces a residue alpha-amino- or
 subset: PSI-MOD-slim
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00670
+is_a: MOD:00670 ! N-acylated residue
 
 [Term]
 id: MOD:01707
@@ -30883,7 +30886,7 @@ name: isotope tagged reagent O-acylated residue
 def: "A protein modification that effectively replaces a residue hydroxyl group with an isotope tagged reagent acyloxy group." [PubMed:18688235]
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00671
+is_a: MOD:00671 ! O-acylated residue
 
 [Term]
 id: MOD:01708
@@ -30893,9 +30896,9 @@ subset: PSI-MOD-slim
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:01696
-is_a: MOD:01705
-is_a: MOD:01706
+is_a: MOD:01696 ! alpha-amino acylated residue
+is_a: MOD:01705 ! isotope tagged reagent acylated residue
+is_a: MOD:01706 ! isotope tagged reagent N-acylated residue
 
 [Term]
 id: MOD:01709
@@ -30906,7 +30909,7 @@ subset: PSI-MOD-slim
 synonym: "(4-methylpiperazin-1-yl)acetyl" EXACT PSI-MOD-alternate []
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01706
+is_a: MOD:01706 ! isotope tagged reagent N-acylated residue
 
 [Term]
 id: MOD:01710
@@ -30916,7 +30919,7 @@ comment: The reagent consists of a reporter group, a balance group and a protein
 synonym: "(4-methylpiperazin-1-yl)acetyl" EXACT PSI-MOD-alternate []
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01706
+is_a: MOD:01706 ! isotope tagged reagent N-acylated residue
 
 [Term]
 id: MOD:01711
@@ -30929,8 +30932,8 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:214
-is_a: MOD:01708
-is_a: MOD:01709
+is_a: MOD:01708 ! isotope tagged reagent alpha-amino acylated residue
+is_a: MOD:01709 ! iTRAQ4plex reporter+balance reagent N-acylated residue
 
 [Term]
 id: MOD:01712
@@ -30943,8 +30946,8 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:214
-is_a: MOD:01708
-is_a: MOD:01710
+is_a: MOD:01708 ! isotope tagged reagent alpha-amino acylated residue
+is_a: MOD:01710 ! iTRAQ8plex reporter+balance reagent N-acylated residue
 
 [Term]
 id: MOD:01713
@@ -30954,7 +30957,7 @@ comment: The reagent consists of a reporter group, a balance group and a protein
 synonym: "(4-methylpiperazin-1-yl)acetyl" EXACT PSI-MOD-alternate []
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01707
+is_a: MOD:01707 ! isotope tagged reagent O-acylated residue
 
 [Term]
 id: MOD:01714
@@ -30964,7 +30967,7 @@ comment: The reagent consists of a reporter group, a balance group and a protein
 synonym: "(4-methylpiperazin-1-yl)acetyl" EXACT PSI-MOD-alternate []
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01707
+is_a: MOD:01707 ! isotope tagged reagent O-acylated residue
 
 [Term]
 id: MOD:01715
@@ -30981,10 +30984,10 @@ property_value: DiffMono "229.162932" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:214
-is_a: MOD:01426
-is_a: MOD:01428
-is_a: MOD:01429
-is_a: MOD:01705
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
+is_a: MOD:01428 ! (13)C isotope tagged reagent
+is_a: MOD:01429 ! (15)N isotope tagged reagent
+is_a: MOD:01705 ! isotope tagged reagent acylated residue
 
 [Term]
 id: MOD:01716
@@ -30993,9 +30996,9 @@ def: "The protein modification reporter fragment produced by an Proteome Science
 subset: PSI-MOD-slim
 synonym: "2,6-dimethyl-1-methylidenepiperidinium" EXACT PSI-MOD-alternate []
 synonym: "cysTMT6plex reporter fragment" EXACT PSI-MOD-alternate []
-is_a: MOD:01520
-relationship: derives_from MOD:01715
-relationship: derives_from MOD:01821
+is_a: MOD:01520 ! modification reporter fragment
+relationship: derives_from MOD:01715 ! TMT6plex reporter+balance reagent acylated residue
+relationship: derives_from MOD:01821 ! cysTMT6plex reporter+balance reagent cysteine disulfide
 
 [Term]
 id: MOD:01717
@@ -31008,7 +31011,7 @@ synonym: "Sixplex Tandem Mass Tag(TM)" RELATED Unimod-description []
 synonym: "TMT6plex" RELATED Unimod-alternate []
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01706
+is_a: MOD:01706 ! isotope tagged reagent N-acylated residue
 
 [Term]
 id: MOD:01718
@@ -31023,8 +31026,8 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:214
-is_a: MOD:01708
-is_a: MOD:01717
+is_a: MOD:01708 ! isotope tagged reagent alpha-amino acylated residue
+is_a: MOD:01717 ! TMT6plex reporter+balance reagent N-acylated residue
 
 [Term]
 id: MOD:01719
@@ -31036,7 +31039,7 @@ synonym: "Sixplex Tandem Mass Tag(TM)" RELATED Unimod-description []
 synonym: "TMT6plex" RELATED Unimod-alternate []
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01707
+is_a: MOD:01707 ! isotope tagged reagent O-acylated residue
 
 [Term]
 id: MOD:01720
@@ -31053,7 +31056,7 @@ property_value: DiffMono "229.162932" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:737
-is_a: MOD:01715
+is_a: MOD:01715 ! TMT6plex reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01721
@@ -31071,8 +31074,8 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:737
-is_a: MOD:01718
-is_a: MOD:01720
+is_a: MOD:01718 ! TMT6plex reporter+balance reagent acylated N-terminal
+is_a: MOD:01720 ! TMT6plex-126 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01722
@@ -31092,9 +31095,9 @@ property_value: MassMono "357.257895" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:737
-is_a: MOD:01717
-is_a: MOD:01720
-is_a: MOD:01875
+is_a: MOD:01717 ! TMT6plex reporter+balance reagent N-acylated residue
+is_a: MOD:01720 ! TMT6plex-126 reporter+balance reagent acylated residue
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01723
@@ -31113,9 +31116,9 @@ property_value: MassMono "392.226261" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:737
-is_a: MOD:00919
-is_a: MOD:01719
-is_a: MOD:01720
+is_a: MOD:00919 ! modified L-tyrosine residue
+is_a: MOD:01719 ! TMT6plex reporter+balance reagent O-acylated residue
+is_a: MOD:01720 ! TMT6plex-126 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01724
@@ -31133,9 +31136,9 @@ property_value: MassAvg "366.22" xsd:float
 property_value: MassMono "366.221844" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00909
-is_a: MOD:01717
-is_a: MOD:01720
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:01717 ! TMT6plex reporter+balance reagent N-acylated residue
+is_a: MOD:01720 ! TMT6plex-126 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01725
@@ -31153,9 +31156,9 @@ property_value: MassAvg "316.19" xsd:float
 property_value: MassMono "316.194961" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02003
-is_a: MOD:01719
-is_a: MOD:01720
+is_a: MOD:02003 ! O3-acylated L-serine
+is_a: MOD:01719 ! TMT6plex reporter+balance reagent O-acylated residue
+is_a: MOD:01720 ! TMT6plex-126 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01726
@@ -31173,9 +31176,9 @@ property_value: MassAvg "330.21" xsd:float
 property_value: MassMono "330.210611" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02004
-is_a: MOD:01719
-is_a: MOD:01720
+is_a: MOD:02004 ! O3-acylated L-threonine
+is_a: MOD:01719 ! TMT6plex reporter+balance reagent O-acylated residue
+is_a: MOD:01720 ! TMT6plex-126 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01727
@@ -31192,10 +31195,10 @@ property_value: MassAvg "126.13" xsd:float
 property_value: MassMono "126.127726" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01716
-relationship: derives_from MOD:01720
-relationship: derives_from MOD:01822
-relationship: derives_from MOD:01823
+is_a: MOD:01716 ! TMT6plex reporter fragment
+relationship: derives_from MOD:01720 ! TMT6plex-126 reporter+balance reagent acylated residue
+relationship: derives_from MOD:01822 ! cysTMT6plex-zero reporter+balance reagent cysteine disulfide
+relationship: derives_from MOD:01823 ! cysTMT6plex-126 reporter+balance reagent cysteine disulfide
 
 [Term]
 id: MOD:01728
@@ -31212,7 +31215,7 @@ property_value: DiffMono "229.162932" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:737
-is_a: MOD:01715
+is_a: MOD:01715 ! TMT6plex reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01729
@@ -31229,8 +31232,8 @@ property_value: DiffMono "229.162932" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:01718
-is_a: MOD:01728
+is_a: MOD:01718 ! TMT6plex reporter+balance reagent acylated N-terminal
+is_a: MOD:01728 ! TMT6plex-127 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01730
@@ -31250,9 +31253,9 @@ property_value: MassMono "357.257895" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:737
-is_a: MOD:01717
-is_a: MOD:01728
-is_a: MOD:01875
+is_a: MOD:01717 ! TMT6plex reporter+balance reagent N-acylated residue
+is_a: MOD:01728 ! TMT6plex-127 reporter+balance reagent acylated residue
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01731
@@ -31270,9 +31273,9 @@ property_value: MassAvg "229.16" xsd:float
 property_value: MassMono "229.162932" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00919
-is_a: MOD:01719
-is_a: MOD:01728
+is_a: MOD:00919 ! modified L-tyrosine residue
+is_a: MOD:01719 ! TMT6plex reporter+balance reagent O-acylated residue
+is_a: MOD:01728 ! TMT6plex-127 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01732
@@ -31290,9 +31293,9 @@ property_value: MassAvg "366.22" xsd:float
 property_value: MassMono "366.221844" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00909
-is_a: MOD:01717
-is_a: MOD:01728
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:01717 ! TMT6plex reporter+balance reagent N-acylated residue
+is_a: MOD:01728 ! TMT6plex-127 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01733
@@ -31310,9 +31313,9 @@ property_value: MassAvg "316.19" xsd:float
 property_value: MassMono "316.194961" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02003
-is_a: MOD:01719
-is_a: MOD:01728
+is_a: MOD:02003 ! O3-acylated L-serine
+is_a: MOD:01719 ! TMT6plex reporter+balance reagent O-acylated residue
+is_a: MOD:01728 ! TMT6plex-127 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01734
@@ -31330,9 +31333,9 @@ property_value: MassAvg "330.21" xsd:float
 property_value: MassMono "330.210611" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02004
-is_a: MOD:01719
-is_a: MOD:01728
+is_a: MOD:02004 ! O3-acylated L-threonine
+is_a: MOD:01719 ! TMT6plex reporter+balance reagent O-acylated residue
+is_a: MOD:01728 ! TMT6plex-127 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01735
@@ -31349,9 +31352,9 @@ property_value: MassAvg "127.13" xsd:float
 property_value: MassMono "127.131081" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01716
-relationship: derives_from MOD:01728
-relationship: derives_from MOD:01824
+is_a: MOD:01716 ! TMT6plex reporter fragment
+relationship: derives_from MOD:01728 ! TMT6plex-127 reporter+balance reagent acylated residue
+relationship: derives_from MOD:01824 ! cysTMT6plex-127 reporter+balance reagent cysteine disulfide
 
 [Term]
 id: MOD:01736
@@ -31368,7 +31371,7 @@ property_value: DiffMono "229.162932" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:737
-is_a: MOD:01715
+is_a: MOD:01715 ! TMT6plex reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01737
@@ -31386,8 +31389,8 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:737
-is_a: MOD:01718
-is_a: MOD:01736
+is_a: MOD:01718 ! TMT6plex reporter+balance reagent acylated N-terminal
+is_a: MOD:01736 ! TMT6plex-128 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01738
@@ -31407,9 +31410,9 @@ property_value: MassMono "357.257895" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:737
-is_a: MOD:01717
-is_a: MOD:01736
-is_a: MOD:01875
+is_a: MOD:01717 ! TMT6plex reporter+balance reagent N-acylated residue
+is_a: MOD:01736 ! TMT6plex-128 reporter+balance reagent acylated residue
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01739
@@ -31428,9 +31431,9 @@ property_value: MassMono "392.226261" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:737
-is_a: MOD:00919
-is_a: MOD:01719
-is_a: MOD:01736
+is_a: MOD:00919 ! modified L-tyrosine residue
+is_a: MOD:01719 ! TMT6plex reporter+balance reagent O-acylated residue
+is_a: MOD:01736 ! TMT6plex-128 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01740
@@ -31448,9 +31451,9 @@ property_value: MassAvg "366.22" xsd:float
 property_value: MassMono "366.221844" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00909
-is_a: MOD:01717
-is_a: MOD:01736
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:01717 ! TMT6plex reporter+balance reagent N-acylated residue
+is_a: MOD:01736 ! TMT6plex-128 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01741
@@ -31468,9 +31471,9 @@ property_value: MassAvg "316.19" xsd:float
 property_value: MassMono "316.194961" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02003
-is_a: MOD:01719
-is_a: MOD:01736
+is_a: MOD:02003 ! O3-acylated L-serine
+is_a: MOD:01719 ! TMT6plex reporter+balance reagent O-acylated residue
+is_a: MOD:01736 ! TMT6plex-128 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01742
@@ -31488,9 +31491,9 @@ property_value: MassAvg "330.21" xsd:float
 property_value: MassMono "330.210611" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02004
-is_a: MOD:01719
-is_a: MOD:01736
+is_a: MOD:02004 ! O3-acylated L-threonine
+is_a: MOD:01719 ! TMT6plex reporter+balance reagent O-acylated residue
+is_a: MOD:01736 ! TMT6plex-128 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01743
@@ -31507,9 +31510,9 @@ property_value: MassAvg "128.13" xsd:float
 property_value: MassMono "128.134436" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01716
-relationship: derives_from MOD:01736
-relationship: derives_from MOD:01825
+is_a: MOD:01716 ! TMT6plex reporter fragment
+relationship: derives_from MOD:01736 ! TMT6plex-128 reporter+balance reagent acylated residue
+relationship: derives_from MOD:01825 ! cysTMT6plex-128 reporter+balance reagent cysteine disulfide
 
 [Term]
 id: MOD:01744
@@ -31526,7 +31529,7 @@ property_value: DiffMono "229.162932" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:737
-is_a: MOD:01715
+is_a: MOD:01715 ! TMT6plex reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01745
@@ -31544,8 +31547,8 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:737
-is_a: MOD:01718
-is_a: MOD:01744
+is_a: MOD:01718 ! TMT6plex reporter+balance reagent acylated N-terminal
+is_a: MOD:01744 ! TMT6plex-129 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01746
@@ -31565,9 +31568,9 @@ property_value: MassMono "357.257895" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:737
-is_a: MOD:01717
-is_a: MOD:01744
-is_a: MOD:01875
+is_a: MOD:01717 ! TMT6plex reporter+balance reagent N-acylated residue
+is_a: MOD:01744 ! TMT6plex-129 reporter+balance reagent acylated residue
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01747
@@ -31586,9 +31589,9 @@ property_value: MassMono "392.226261" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:737
-is_a: MOD:00919
-is_a: MOD:01719
-is_a: MOD:01744
+is_a: MOD:00919 ! modified L-tyrosine residue
+is_a: MOD:01719 ! TMT6plex reporter+balance reagent O-acylated residue
+is_a: MOD:01744 ! TMT6plex-129 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01748
@@ -31606,9 +31609,9 @@ property_value: MassAvg "366.22" xsd:float
 property_value: MassMono "366.221844" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00909
-is_a: MOD:01717
-is_a: MOD:01744
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:01717 ! TMT6plex reporter+balance reagent N-acylated residue
+is_a: MOD:01744 ! TMT6plex-129 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01749
@@ -31626,9 +31629,9 @@ property_value: MassAvg "316.19" xsd:float
 property_value: MassMono "316.194961" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02003
-is_a: MOD:01719
-is_a: MOD:01744
+is_a: MOD:02003 ! O3-acylated L-serine
+is_a: MOD:01719 ! TMT6plex reporter+balance reagent O-acylated residue
+is_a: MOD:01744 ! TMT6plex-129 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01750
@@ -31646,9 +31649,9 @@ property_value: MassAvg "330.21" xsd:float
 property_value: MassMono "330.210611" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02004
-is_a: MOD:01719
-is_a: MOD:01744
+is_a: MOD:02004 ! O3-acylated L-threonine
+is_a: MOD:01719 ! TMT6plex reporter+balance reagent O-acylated residue
+is_a: MOD:01744 ! TMT6plex-129 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01751
@@ -31665,9 +31668,9 @@ property_value: MassAvg "129.14" xsd:float
 property_value: MassMono "129.137790" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01716
-relationship: derives_from MOD:01744
-relationship: derives_from MOD:01826
+is_a: MOD:01716 ! TMT6plex reporter fragment
+relationship: derives_from MOD:01744 ! TMT6plex-129 reporter+balance reagent acylated residue
+relationship: derives_from MOD:01826 ! cysTMT6plex-129 reporter+balance reagent cysteine disulfide
 
 [Term]
 id: MOD:01752
@@ -31684,8 +31687,8 @@ property_value: DiffMono "229.162932" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:737
-is_a: MOD:01715
-relationship: derives_from MOD:01827
+is_a: MOD:01715 ! TMT6plex reporter+balance reagent acylated residue
+relationship: derives_from MOD:01827 ! cysTMT6plex-130 reporter+balance reagent cysteine disulfide
 
 [Term]
 id: MOD:01753
@@ -31703,8 +31706,8 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:737
-is_a: MOD:01718
-is_a: MOD:01752
+is_a: MOD:01718 ! TMT6plex reporter+balance reagent acylated N-terminal
+is_a: MOD:01752 ! TMT6plex-130 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01754
@@ -31724,9 +31727,9 @@ property_value: MassMono "357.257895" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:737
-is_a: MOD:01717
-is_a: MOD:01752
-is_a: MOD:01875
+is_a: MOD:01717 ! TMT6plex reporter+balance reagent N-acylated residue
+is_a: MOD:01752 ! TMT6plex-130 reporter+balance reagent acylated residue
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01755
@@ -31745,9 +31748,9 @@ property_value: MassMono "392.226261" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:737
-is_a: MOD:00919
-is_a: MOD:01719
-is_a: MOD:01752
+is_a: MOD:00919 ! modified L-tyrosine residue
+is_a: MOD:01719 ! TMT6plex reporter+balance reagent O-acylated residue
+is_a: MOD:01752 ! TMT6plex-130 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01756
@@ -31765,9 +31768,9 @@ property_value: MassAvg "366.22" xsd:float
 property_value: MassMono "366.221844" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00909
-is_a: MOD:01717
-is_a: MOD:01752
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:01717 ! TMT6plex reporter+balance reagent N-acylated residue
+is_a: MOD:01752 ! TMT6plex-130 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01757
@@ -31785,9 +31788,9 @@ property_value: MassAvg "316.19" xsd:float
 property_value: MassMono "316.194961" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02003
-is_a: MOD:01719
-is_a: MOD:01752
+is_a: MOD:02003 ! O3-acylated L-serine
+is_a: MOD:01719 ! TMT6plex reporter+balance reagent O-acylated residue
+is_a: MOD:01752 ! TMT6plex-130 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01758
@@ -31805,9 +31808,9 @@ property_value: MassAvg "330.21" xsd:float
 property_value: MassMono "330.210611" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02004
-is_a: MOD:01719
-is_a: MOD:01752
+is_a: MOD:02004 ! O3-acylated L-threonine
+is_a: MOD:01719 ! TMT6plex reporter+balance reagent O-acylated residue
+is_a: MOD:01752 ! TMT6plex-130 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01759
@@ -31824,8 +31827,8 @@ property_value: MassAvg "130.14" xsd:float
 property_value: MassMono "130.141145" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01716
-relationship: derives_from MOD:01752
+is_a: MOD:01716 ! TMT6plex reporter fragment
+relationship: derives_from MOD:01752 ! TMT6plex-130 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01760
@@ -31843,8 +31846,8 @@ property_value: DiffMono "229.162932" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:737
-is_a: MOD:01715
-relationship: derives_from MOD:01828
+is_a: MOD:01715 ! TMT6plex reporter+balance reagent acylated residue
+relationship: derives_from MOD:01828 ! cysTMT6plex-131 reporter+balance reagent cysteine disulfide
 
 [Term]
 id: MOD:01761
@@ -31862,8 +31865,8 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:737
-is_a: MOD:01718
-is_a: MOD:01760
+is_a: MOD:01718 ! TMT6plex reporter+balance reagent acylated N-terminal
+is_a: MOD:01760 ! TMT6plex-131 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01762
@@ -31883,9 +31886,9 @@ property_value: MassMono "357.257895" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:737
-is_a: MOD:01717
-is_a: MOD:01760
-is_a: MOD:01875
+is_a: MOD:01717 ! TMT6plex reporter+balance reagent N-acylated residue
+is_a: MOD:01760 ! TMT6plex-131 reporter+balance reagent acylated residue
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01763
@@ -31904,9 +31907,9 @@ property_value: MassMono "392.226261" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:737
-is_a: MOD:00919
-is_a: MOD:01719
-is_a: MOD:01760
+is_a: MOD:00919 ! modified L-tyrosine residue
+is_a: MOD:01719 ! TMT6plex reporter+balance reagent O-acylated residue
+is_a: MOD:01760 ! TMT6plex-131 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01764
@@ -31924,9 +31927,9 @@ property_value: MassAvg "366.22" xsd:float
 property_value: MassMono "366.221844" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00909
-is_a: MOD:01717
-is_a: MOD:01760
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:01717 ! TMT6plex reporter+balance reagent N-acylated residue
+is_a: MOD:01760 ! TMT6plex-131 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01765
@@ -31944,9 +31947,9 @@ property_value: MassAvg "316.19" xsd:float
 property_value: MassMono "316.194961" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02003
-is_a: MOD:01719
-is_a: MOD:01760
+is_a: MOD:02003 ! O3-acylated L-serine
+is_a: MOD:01719 ! TMT6plex reporter+balance reagent O-acylated residue
+is_a: MOD:01760 ! TMT6plex-131 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01766
@@ -31964,9 +31967,9 @@ property_value: MassAvg "330.21" xsd:float
 property_value: MassMono "330.210611" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02004
-is_a: MOD:01719
-is_a: MOD:01760
+is_a: MOD:02004 ! O3-acylated L-threonine
+is_a: MOD:01719 ! TMT6plex reporter+balance reagent O-acylated residue
+is_a: MOD:01760 ! TMT6plex-131 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01767
@@ -31981,8 +31984,8 @@ property_value: MassAvg "131.14" xsd:float
 property_value: MassMono "131.138180" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01716
-relationship: derives_from MOD:01760
+is_a: MOD:01716 ! TMT6plex reporter fragment
+relationship: derives_from MOD:01760 ! TMT6plex-131 reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01768
@@ -31994,8 +31997,8 @@ property_value: DiffFormula "C 16 H 28 N 0 O 1" xsd:string
 property_value: DiffMono "236.214016" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00671
-is_a: MOD:01423
+is_a: MOD:00671 ! O-acylated residue
+is_a: MOD:01423 ! palmitoleylated residue
 
 [Term]
 id: MOD:01769
@@ -32018,8 +32021,8 @@ property_value: MassMono "337.261694" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:431
-is_a: MOD:02004
-is_a: MOD:01768
+is_a: MOD:02004 ! O3-acylated L-threonine
+is_a: MOD:01768 ! O-palmitoleylated residue
 
 [Term]
 id: MOD:01770
@@ -32036,9 +32039,9 @@ property_value: MassMono "355.296068" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
-is_a: MOD:02004
-relationship: has_functional_parent MOD:00088
-relationship: has_functional_parent MOD:00106
+is_a: MOD:02004 ! O3-acylated L-threonine
+relationship: has_functional_parent MOD:00088 ! O-palmitoyl-L-threonine
+relationship: has_functional_parent MOD:00106 ! L-threonine amide
 
 [Term]
 id: MOD:01771
@@ -32054,8 +32057,8 @@ property_value: MassAvg "205.36" xsd:float
 property_value: MassMono "205.195077" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:01520
-relationship: derives_from MOD:00437
+is_a: MOD:01520 ! modification reporter fragment
+relationship: derives_from MOD:00437 ! farnesylated residue
 
 [Term]
 id: MOD:01772
@@ -32070,8 +32073,8 @@ property_value: MassAvg "239.42" xsd:float
 property_value: MassMono "239.236942" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:01520
-relationship: derives_from MOD:00440
+is_a: MOD:01520 ! modification reporter fragment
+relationship: derives_from MOD:00440 ! palmitoylated residue
 
 [Term]
 id: MOD:01773
@@ -32088,9 +32091,9 @@ property_value: MassAvg "112.15" xsd:float
 property_value: MassMono "112.075690" xsd:float
 property_value: Origin "MOD:00083" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00431
-is_a: MOD:00912
-relationship: derives_from MOD:00083
+is_a: MOD:00431 ! modified residue with a secondary neutral loss
+is_a: MOD:00912 ! modified L-lysine residue
+relationship: derives_from MOD:00083 ! N6,N6,N6-trimethyl-L-lysine
 
 [Term]
 id: MOD:01774
@@ -32110,8 +32113,8 @@ property_value: MassAvg "254.37" xsd:float
 property_value: MassMono "254.199428" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00666
-is_a: MOD:01875
+is_a: MOD:00666 ! octanoylated residue
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01775
@@ -32129,7 +32132,7 @@ property_value: MassAvg "287.32" xsd:float
 property_value: MassMono "287.126991" xsd:float
 property_value: Origin "Q" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00907
+is_a: MOD:00907 ! modified L-glutamine residue
 
 [Term]
 id: MOD:01776
@@ -32149,8 +32152,8 @@ property_value: MassAvg "220.31" xsd:float
 property_value: MassMono "220.034020" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
-is_a: MOD:00905
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:01777
@@ -32172,7 +32175,7 @@ property_value: MassMono "177.033388" xsd:float
 property_value: Origin "G" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
-is_a: MOD:00908
+is_a: MOD:00908 ! modified glycine residue
 
 [Term]
 id: MOD:01778
@@ -32192,7 +32195,7 @@ property_value: Origin "G" xsd:string
 property_value: Source "hypothetical" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0433
-is_a: MOD:00908
+is_a: MOD:00908 ! modified glycine residue
 
 [Term]
 id: MOD:01779
@@ -32210,7 +32213,7 @@ property_value: MassAvg "256.35" xsd:float
 property_value: MassMono "256.189926" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:01875
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01780
@@ -32232,8 +32235,8 @@ property_value: MassMono "272.184841" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: uniprot.ptm:PTM-0474
-relationship: derives_from MOD:00037
-is_a: MOD:01875
+relationship: derives_from MOD:00037 ! 5-hydroxy-L-lysine
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01781
@@ -32260,8 +32263,8 @@ property_value: Origin "K" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: Unimod:1289
 xref: uniprot.ptm:PTM-0637
-is_a: MOD:01875
-is_a: MOD:01997
+is_a: MOD:01875 ! N6-acylated L-lysine
+is_a: MOD:01997 ! N-butanoylated residue
 
 [Term]
 id: MOD:01782
@@ -32281,8 +32284,8 @@ property_value: MassMono "101.047678" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0432
-is_a: MOD:01680
-is_a: MOD:01800
+is_a: MOD:01680 ! alpha-amino monomethylated residue
+is_a: MOD:01800 ! N-methylated serine
 
 [Term]
 id: MOD:01783
@@ -32302,8 +32305,8 @@ property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0431
-is_a: MOD:01686
-is_a: MOD:01800
+is_a: MOD:01686 ! alpha-amino dimethylated residue
+is_a: MOD:01800 ! N-methylated serine
 
 [Term]
 id: MOD:01784
@@ -32328,8 +32331,8 @@ property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0430
-is_a: MOD:01698
-is_a: MOD:01800
+is_a: MOD:01698 ! alpha-amino trimethylated protonated-residue
+is_a: MOD:01800 ! N-methylated serine
 
 [Term]
 id: MOD:01785
@@ -32350,8 +32353,8 @@ property_value: MassAvg "230.22" xsd:float
 property_value: MassMono "230.090272" xsd:float
 property_value: Origin "T" xsd:string
 property_value: Source "hypothetical" xsd:string
-is_a: MOD:00671
-is_a: MOD:01979
+is_a: MOD:00671 ! O-acylated residue
+is_a: MOD:01979 ! O-(L-isoglutamyl)-L-threonine
 
 [Term]
 id: MOD:01786
@@ -32374,7 +32377,7 @@ property_value: MassMono "208.048407" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0434
-is_a: MOD:01352
+is_a: MOD:01352 ! nitrated L-tyrosine
 
 [Term]
 id: MOD:01787
@@ -32396,8 +32399,8 @@ property_value: MassMono "339.121906" xsd:float
 property_value: Origin "Y, Y" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: uniprot.ptm:PTM-0320
-is_a: MOD:00692
-is_a: MOD:02058
+is_a: MOD:00692 ! uncategorized crosslinked residues
+is_a: MOD:02058 ! crosslinked L-tyrosine residue
 
 [Term]
 id: MOD:01788
@@ -32415,8 +32418,8 @@ property_value: MassAvg "110.14" xsd:float
 property_value: MassMono "110.071274" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00909
-is_a: MOD:01527
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:01527 ! residue reporter fragment
 
 [Term]
 id: MOD:01789
@@ -32434,8 +32437,8 @@ property_value: MassAvg "120.17" xsd:float
 property_value: MassMono "120.080776" xsd:float
 property_value: Origin "F" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00914
-is_a: MOD:01527
+is_a: MOD:00914 ! modified L-phenylalanine residue
+is_a: MOD:01527 ! residue reporter fragment
 
 [Term]
 id: MOD:01790
@@ -32453,8 +32456,8 @@ property_value: MassAvg "136.17" xsd:float
 property_value: MassMono "136.075690" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00919
-is_a: MOD:01527
+is_a: MOD:00919 ! modified L-tyrosine residue
+is_a: MOD:01527 ! residue reporter fragment
 
 [Term]
 id: MOD:01791
@@ -32472,9 +32475,9 @@ property_value: MassAvg "190.12" xsd:float
 property_value: MassMono "190.037604" xsd:float
 property_value: Origin "MOD:00890" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00909
-is_a: MOD:01527
-relationship: derives_from MOD:00890
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:01527 ! residue reporter fragment
+relationship: derives_from MOD:00890 ! phosphorylated L-histidine
 
 [Term]
 id: MOD:01792
@@ -32492,9 +32495,9 @@ property_value: MassAvg "216.15" xsd:float
 property_value: MassMono "216.042021" xsd:float
 property_value: Origin "MOD:00048" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00919
-is_a: MOD:01527
-relationship: derives_from MOD:00048
+is_a: MOD:00919 ! modified L-tyrosine residue
+is_a: MOD:01527 ! residue reporter fragment
+relationship: derives_from MOD:00048 ! O4'-phospho-L-tyrosine
 
 [Term]
 id: MOD:01793
@@ -32510,9 +32513,9 @@ property_value: MassAvg "176.19" xsd:float
 property_value: MassMono "176.025563" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00708
-is_a: MOD:01854
-relationship: derives_from MOD:01060
+is_a: MOD:00708 ! sulfur oxygenated L-cysteine
+is_a: MOD:01854 ! sulfur monooxygenated residue
+relationship: derives_from MOD:01060 ! S-carboxamidomethyl-L-cysteine
 
 [Term]
 id: MOD:01794
@@ -32524,8 +32527,8 @@ property_value: DiffFormula "(13)C 1 (1)H -1 (2)H 3" xsd:string
 property_value: DiffMono "18.037835" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00839
-is_a: MOD:00842
+is_a: MOD:00839 ! (2)H deuterium labeled residue
+is_a: MOD:00842 ! (13)C labeled residue
 
 [Term]
 id: MOD:01795
@@ -32540,9 +32543,9 @@ property_value: MassAvg "135.06" xsd:float
 property_value: MassMono "135.062670" xsd:float
 property_value: Origin "M" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00839
-is_a: MOD:00842
-is_a: MOD:00913
+is_a: MOD:00839 ! (2)H deuterium labeled residue
+is_a: MOD:00842 ! (13)C labeled residue
+is_a: MOD:00913 ! modified L-methionine residue
 
 [Term]
 id: MOD:01796
@@ -32556,8 +32559,8 @@ property_value: MassAvg "151.06" xsd:float
 property_value: MassMono "151.057585" xsd:float
 property_value: Origin "M" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00839
-is_a: MOD:00913
+is_a: MOD:00839 ! (2)H deuterium labeled residue
+is_a: MOD:00913 ! modified L-methionine residue
 
 [Term]
 id: MOD:01797
@@ -32575,8 +32578,8 @@ property_value: MassAvg "190.12" xsd:float
 property_value: MassMono "190.037604" xsd:float
 property_value: Origin "MOD:00044" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01791
-relationship: derives_from MOD:00044
+is_a: MOD:01791 ! phosphohistidine immonium ion
+relationship: derives_from MOD:00044 ! 1'-phospho-L-histidine
 
 [Term]
 id: MOD:01798
@@ -32594,8 +32597,8 @@ property_value: MassAvg "190.12" xsd:float
 property_value: MassMono "190.037604" xsd:float
 property_value: Origin "MOD:00045" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01791
-relationship: derives_from MOD:00045
+is_a: MOD:01791 ! phosphohistidine immonium ion
+relationship: derives_from MOD:00045 ! 3'-phospho-L-histidine
 
 [Term]
 id: MOD:01799
@@ -32604,8 +32607,8 @@ def: "A protein modification that effectively converts an L-alanine residue to a
 subset: PSI-MOD-slim
 synonym: "MeSer" EXACT PSI-MOD-label []
 property_value: Origin "S" xsd:string
-is_a: MOD:00427
-is_a: MOD:00916
+is_a: MOD:00427 ! methylated residue
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:01800
@@ -32615,8 +32618,8 @@ subset: PSI-MOD-slim
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:01460
-is_a: MOD:01799
+is_a: MOD:01460 ! alpha-amino methylated residue
+is_a: MOD:01799 ! methylated serine
 
 [Term]
 id: MOD:01801
@@ -32633,8 +32636,8 @@ property_value: MassMono "89.047130" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00916
-is_a: MOD:01700
+is_a: MOD:00916 ! modified L-serine residue
+is_a: MOD:01700 ! alpha-amino protonated residue
 
 [Term]
 id: MOD:01802
@@ -32653,8 +32656,8 @@ property_value: MassMono "131.094080" xsd:float
 property_value: Origin "MOD:01801" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:01687
-relationship: derives_from MOD:01801
+is_a: MOD:01687 ! alpha-amino trimethylated residue
+relationship: derives_from MOD:01801 ! protonated L-serine (L-serinium) residue
 
 [Term]
 id: MOD:01803
@@ -32663,15 +32666,15 @@ def: "A protein modification that effectively converts an L-threonine residue to
 synonym: "OMeThr" EXACT PSI-MOD-label []
 property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00393
-is_a: MOD:01418
+is_a: MOD:00393 ! O-methylated residue
+is_a: MOD:01418 ! methylated threonine
 
 [Term]
 id: MOD:01804
 name: glycosylphosphorylated residue
 def: "A protein modification that effectively results from forming an adduct with a glycosylphosphate through a phosphodiester bond." [PubMed:18688235]
-is_a: MOD:00764
-is_a: MOD:00861
+is_a: MOD:00764 ! glycoconjugated residue
+is_a: MOD:00861 ! phosphorus containing modified residue
 
 [Term]
 id: MOD:01805
@@ -32696,9 +32699,9 @@ property_value: Origin "D, G" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0490
-is_a: MOD:02043
-is_a: MOD:00954
-is_a: MOD:01928
+is_a: MOD:02043 ! crosslinked L-aspartic acid residue
+is_a: MOD:00954 ! crosslinked residues with loss of water
+is_a: MOD:01928 ! N-(L-isoaspartyl)-glycine
 
 [Term]
 id: MOD:01806
@@ -32720,8 +32723,8 @@ property_value: Origin "L" xsd:string
 property_value: Source "hypothetical" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0435
-is_a: MOD:01686
-is_a: MOD:01808
+is_a: MOD:01686 ! alpha-amino dimethylated residue
+is_a: MOD:01808 ! N-methylated leucine
 
 [Term]
 id: MOD:01807
@@ -32741,8 +32744,8 @@ property_value: MassMono "158.045333" xsd:float
 property_value: Origin "E" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00409
-is_a: MOD:00906
+is_a: MOD:00409 ! N-formylated residue
+is_a: MOD:00906 ! modified L-glutamic acid residue
 
 [Term]
 id: MOD:01808
@@ -32751,8 +32754,8 @@ def: "A protein modification that effectively replaces an L-leucine alpha amino
 subset: PSI-MOD-slim
 synonym: "MeLeu" EXACT PSI-MOD-label []
 property_value: Origin "L" xsd:string
-is_a: MOD:00662
-is_a: MOD:01460
+is_a: MOD:00662 ! methylated leucine
+is_a: MOD:01460 ! alpha-amino methylated residue
 
 [Term]
 id: MOD:01809
@@ -32766,8 +32769,8 @@ property_value: DiffMono "6.013809" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:268
-is_a: MOD:00842
-is_a: MOD:00843
+is_a: MOD:00842 ! (13)C labeled residue
+is_a: MOD:00843 ! (15)N labeled residue
 
 [Term]
 id: MOD:01810
@@ -32784,8 +32787,8 @@ property_value: MassMono "103.066573" xsd:float
 property_value: Origin "P" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:268
-is_a: MOD:00915
-is_a: MOD:01809
+is_a: MOD:00915 ! modified L-proline residue
+is_a: MOD:01809 ! 5x(13)C,1x(15)N labeled residue
 
 [Term]
 id: MOD:01811
@@ -32802,8 +32805,8 @@ property_value: MassMono "137.054294" xsd:float
 property_value: Origin "M" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:268
-is_a: MOD:00913
-is_a: MOD:01809
+is_a: MOD:00913 ! modified L-methionine residue
+is_a: MOD:01809 ! 5x(13)C,1x(15)N labeled residue
 
 [Term]
 id: MOD:01812
@@ -32820,8 +32823,8 @@ property_value: MassMono "153.049209" xsd:float
 property_value: Origin "M" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:268
-relationship: derives_from MOD:00719
-is_a: MOD:01809
+relationship: derives_from MOD:00719 ! L-methionine sulfoxide
+is_a: MOD:01809 ! 5x(13)C,1x(15)N labeled residue
 
 [Term]
 id: MOD:01813
@@ -32837,8 +32840,8 @@ property_value: DiffMono "127.063329" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:29
-is_a: MOD:00649
-is_a: MOD:00848
+is_a: MOD:00649 ! acylated residue
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01814
@@ -32858,9 +32861,9 @@ property_value: MassMono "223.017738" xsd:float
 property_value: Origin "C, S, S" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0454
-is_a: MOD:02044
-is_a: MOD:02055
-is_a: MOD:01425
+is_a: MOD:02044 ! crosslinked L-cysteine residue
+is_a: MOD:02055 ! crosslinked L-serine residue
+is_a: MOD:01425 ! pyridinyl ring crosslinked residues
 
 [Term]
 id: MOD:01815
@@ -32880,9 +32883,9 @@ property_value: MassMono "212.025563" xsd:float
 property_value: Origin "C, E" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0456
-is_a: MOD:02045
-is_a: MOD:01420
-is_a: MOD:02082
+is_a: MOD:02045 ! crosslinked L-glutamic acid residue
+is_a: MOD:01420 ! thiazole/thiazoline ring crosslinked residues
+is_a: MOD:02082 ! didehydrogenated and dehydrated residue
 
 [Term]
 id: MOD:01816
@@ -32901,7 +32904,7 @@ property_value: MassAvg "202.21" xsd:float
 property_value: MassMono "202.074228" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01622
+is_a: MOD:01622 ! monohydroxylated tryptophan
 
 [Term]
 id: MOD:01817
@@ -32920,8 +32923,8 @@ property_value: MassAvg "202.21" xsd:float
 property_value: MassMono "202.074228" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00679
-is_a: MOD:00918
+is_a: MOD:00679 ! carbon oxygenated residue
+is_a: MOD:00918 ! modified L-tryptophan residue
 
 [Term]
 id: MOD:01818
@@ -32943,8 +32946,8 @@ property_value: MassMono "370.142976" xsd:float
 property_value: Origin "W, W" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0544
-is_a: MOD:00692
-is_a: MOD:02057
+is_a: MOD:00692 ! uncategorized crosslinked residues
+is_a: MOD:02057 ! crosslinked L-tryptophan residue
 
 [Term]
 id: MOD:01819
@@ -32967,8 +32970,8 @@ property_value: MassMono "228.111007" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0438
-is_a: MOD:01029
-is_a: MOD:01875
+is_a: MOD:01029 ! succinylated residue
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01820
@@ -32977,8 +32980,8 @@ def: "A protein modification that effectively replaces a cysteine sulhydryl hydr
 subset: PSI-MOD-slim
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00905
-is_a: MOD:01426
+is_a: MOD:00905 ! modified L-cysteine residue
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
 
 [Term]
 id: MOD:01821
@@ -32992,9 +32995,9 @@ synonym: "S-(2-{3-[2-(2,6-dimethylpiperidin-1-yl)acetamido]propanamido}ethyl)sul
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:985
-is_a: MOD:01428
-is_a: MOD:01429
-is_a: MOD:01820
+is_a: MOD:01428 ! (13)C isotope tagged reagent
+is_a: MOD:01429 ! (15)N isotope tagged reagent
+is_a: MOD:01820 ! isotope tagged sufhydryl reagent modified cysteine
 
 [Term]
 id: MOD:01822
@@ -33014,7 +33017,7 @@ property_value: MassMono "420.186498" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:984
-is_a: MOD:01821
+is_a: MOD:01821 ! cysTMT6plex reporter+balance reagent cysteine disulfide
 
 [Term]
 id: MOD:01823
@@ -33034,7 +33037,7 @@ property_value: MassMono "425.196952" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:985
-is_a: MOD:01821
+is_a: MOD:01821 ! cysTMT6plex reporter+balance reagent cysteine disulfide
 
 [Term]
 id: MOD:01824
@@ -33053,7 +33056,7 @@ property_value: MassAvg "425.20" xsd:float
 property_value: MassMono "425.196952" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01821
+is_a: MOD:01821 ! cysTMT6plex reporter+balance reagent cysteine disulfide
 
 [Term]
 id: MOD:01825
@@ -33072,7 +33075,7 @@ property_value: MassAvg "425.20" xsd:float
 property_value: MassMono "425.196952" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01821
+is_a: MOD:01821 ! cysTMT6plex reporter+balance reagent cysteine disulfide
 
 [Term]
 id: MOD:01826
@@ -33091,7 +33094,7 @@ property_value: MassAvg "425.20" xsd:float
 property_value: MassMono "425.196952" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01821
+is_a: MOD:01821 ! cysTMT6plex reporter+balance reagent cysteine disulfide
 
 [Term]
 id: MOD:01827
@@ -33110,7 +33113,7 @@ property_value: MassAvg "425.20" xsd:float
 property_value: MassMono "425.196952" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01821
+is_a: MOD:01821 ! cysTMT6plex reporter+balance reagent cysteine disulfide
 
 [Term]
 id: MOD:01828
@@ -33129,7 +33132,7 @@ property_value: MassAvg "425.20" xsd:float
 property_value: MassMono "425.196952" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01821
+is_a: MOD:01821 ! cysTMT6plex reporter+balance reagent cysteine disulfide
 
 [Term]
 id: MOD:01829
@@ -33144,10 +33147,10 @@ property_value: MassAvg "161.18" xsd:float
 property_value: MassMono "161.014664" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00399
-is_a: MOD:00708
-is_a: MOD:01854
-relationship: derives_from MOD:01061
+is_a: MOD:00399 ! iodoacetic acid derivatized residue
+is_a: MOD:00708 ! sulfur oxygenated L-cysteine
+is_a: MOD:01854 ! sulfur monooxygenated residue
+relationship: derives_from MOD:01061 ! S-carboxymethyl-L-cysteine
 
 [Term]
 id: MOD:01830
@@ -33162,9 +33165,9 @@ property_value: MassAvg "177.17" xsd:float
 property_value: MassMono "177.009579" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00708
-is_a: MOD:01855
-relationship: derives_from MOD:01061
+is_a: MOD:00708 ! sulfur oxygenated L-cysteine
+is_a: MOD:01855 ! sulfur dioxygenated residue
+relationship: derives_from MOD:01061 ! S-carboxymethyl-L-cysteine
 
 [Term]
 id: MOD:01831
@@ -33180,9 +33183,9 @@ property_value: MassAvg "192.19" xsd:float
 property_value: MassMono "192.020478" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00708
-is_a: MOD:01855
-relationship: derives_from MOD:01060
+is_a: MOD:00708 ! sulfur oxygenated L-cysteine
+is_a: MOD:01855 ! sulfur dioxygenated residue
+relationship: derives_from MOD:01060 ! S-carboxamidomethyl-L-cysteine
 
 [Term]
 id: MOD:01832
@@ -33196,7 +33199,7 @@ property_value: DiffMono "5.016774" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:772
-is_a: MOD:00842
+is_a: MOD:00842 ! (13)C labeled residue
 
 [Term]
 id: MOD:01833
@@ -33210,8 +33213,8 @@ property_value: MassAvg "136.06" xsd:float
 property_value: MassMono "136.057259" xsd:float
 property_value: Origin "M" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00913
-is_a: MOD:01832
+is_a: MOD:00913 ! modified L-methionine residue
+is_a: MOD:01832 ! 5x(13)C-labeled residue
 
 [Term]
 id: MOD:01834
@@ -33225,8 +33228,8 @@ property_value: MassAvg "152.05" xsd:float
 property_value: MassMono "152.052174" xsd:float
 property_value: Origin "MOD:00719" xsd:string
 property_value: Source "artifact" xsd:string
-relationship: derives_from MOD:00719
-is_a: MOD:01832
+relationship: derives_from MOD:00719 ! L-methionine sulfoxide
+is_a: MOD:01832 ! 5x(13)C-labeled residue
 
 [Term]
 id: MOD:01835
@@ -33240,8 +33243,8 @@ property_value: MassAvg "168.05" xsd:float
 property_value: MassMono "168.047088" xsd:float
 property_value: Origin "MOD:00256" xsd:string
 property_value: Source "artifact" xsd:string
-relationship: derives_from MOD:00256
-is_a: MOD:01832
+relationship: derives_from MOD:00256 ! L-methionine sulfone
+is_a: MOD:01832 ! 5x(13)C-labeled residue
 
 [Term]
 id: MOD:01836
@@ -33257,8 +33260,8 @@ property_value: MassAvg "365.34" xsd:float
 property_value: MassMono "365.122300" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00848
-is_a: MOD:01875
+is_a: MOD:00848 ! reagent derivatized residue
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01837
@@ -33281,7 +33284,7 @@ property_value: MassAvg "172.20" xsd:float
 property_value: MassMono "172.030649" xsd:float
 property_value: Origin "C, C" xsd:string
 property_value: Source "hypothetical" xsd:string
-is_a: MOD:00687
+is_a: MOD:00687 ! thioether crosslinked residues
 
 [Term]
 id: MOD:01838
@@ -33306,7 +33309,7 @@ property_value: MassMono "215.126991" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0439
-is_a: MOD:01853
+is_a: MOD:01853 ! L-lysinoalanine
 
 [Term]
 id: MOD:01839
@@ -33321,9 +33324,9 @@ property_value: MassAvg "172.20" xsd:float
 property_value: MassMono "172.030649" xsd:float
 property_value: Origin "C, X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00859
-is_a: MOD:01841
-is_a: MOD:00954
+is_a: MOD:00859 ! modified residue that can arise from different natural residues
+is_a: MOD:01841 ! lanthionine
+is_a: MOD:00954 ! crosslinked residues with loss of water
 
 [Term]
 id: MOD:01840
@@ -33346,9 +33349,9 @@ property_value: MassMono "113.084064" xsd:float
 property_value: Origin "I" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0442
-is_a: MOD:00664
-is_a: MOD:00910
-is_a: MOD:00306
+is_a: MOD:00664 ! stereoisomerized residue
+is_a: MOD:00910 ! modified L-isoleucine residue
+is_a: MOD:00306 ! residues isobaric at 113.084064 Da
 
 [Term]
 id: MOD:01841
@@ -33370,8 +33373,8 @@ property_value: MassAvg "172.20" xsd:float
 property_value: MassMono "172.030649" xsd:float
 property_value: Origin "C, X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01993
-is_a: MOD:00954
+is_a: MOD:01993 ! beta-carbon thioether crosslinked residues
+is_a: MOD:00954 ! crosslinked residues with loss of water
 
 [Term]
 id: MOD:01842
@@ -33391,7 +33394,7 @@ property_value: Origin "C, C" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0443
-is_a: MOD:01851
+is_a: MOD:01851 ! S-(2-aminovinyl)-cysteine
 
 [Term]
 id: MOD:01843
@@ -33409,7 +33412,7 @@ property_value: MassMono "220.040341" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0444
-is_a: MOD:01913
+is_a: MOD:01913 ! monochlorinated L-tryptophan
 
 [Term]
 id: MOD:01844
@@ -33430,9 +33433,9 @@ property_value: Origin "C, L" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0448
-is_a: MOD:02044
-is_a: MOD:02050
-is_a: MOD:01856
+is_a: MOD:02044 ! crosslinked L-cysteine residue
+is_a: MOD:02050 ! crosslinked L-leucine residue
+is_a: MOD:01856 ! oxazole/oxazoline ring crosslinked residues (Cys)
 
 [Term]
 id: MOD:01845
@@ -33452,9 +33455,9 @@ property_value: MassMono "196.030649" xsd:float
 property_value: Origin "C, P" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0449
-is_a: MOD:02044
-is_a: MOD:02054
-is_a: MOD:01856
+is_a: MOD:02044 ! crosslinked L-cysteine residue
+is_a: MOD:02054 ! crosslinked L-proline residue
+is_a: MOD:01856 ! oxazole/oxazoline ring crosslinked residues (Cys)
 
 [Term]
 id: MOD:01846
@@ -33473,8 +33476,8 @@ property_value: MassMono "290.859546" xsd:float
 property_value: Origin "C, C" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00742
-is_a: MOD:02067
+is_a: MOD:00742 ! copper containing modified residue
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
 
 [Term]
 id: MOD:01847
@@ -33491,8 +33494,8 @@ property_value: MassAvg "215.12" xsd:float
 property_value: MassMono "214.965345" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "hypothetical" xsd:string
-is_a: MOD:00708
-is_a: MOD:00861
+is_a: MOD:00708 ! sulfur oxygenated L-cysteine
+is_a: MOD:00861 ! phosphorus containing modified residue
 
 [Term]
 id: MOD:01848
@@ -33510,8 +33513,8 @@ property_value: MassAvg "535.68" xsd:float
 property_value: MassMono "535.224674" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00905
-is_a: MOD:01862
+is_a: MOD:00905 ! modified L-cysteine residue
+is_a: MOD:01862 ! disulfide conjugated residue
 
 [Term]
 id: MOD:01849
@@ -33532,7 +33535,7 @@ property_value: Origin "C, C" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
 xref: uniprot.ptm:PTM-0446
-is_a: MOD:01850
+is_a: MOD:01850 ! S-(2-aminovinyl)-D-cysteine
 
 [Term]
 id: MOD:01850
@@ -33548,7 +33551,7 @@ property_value: MassMono "143.027909" xsd:float
 property_value: Origin "C, X" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
-is_a: MOD:01851
+is_a: MOD:01851 ! S-(2-aminovinyl)-cysteine
 
 [Term]
 id: MOD:01851
@@ -33562,8 +33565,8 @@ property_value: MassMono "143.027909" xsd:float
 property_value: Origin "C, X" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
-is_a: MOD:00687
-is_a: MOD:00859
+is_a: MOD:00687 ! thioether crosslinked residues
+is_a: MOD:00859 ! modified residue that can arise from different natural residues
 
 [Term]
 id: MOD:01852
@@ -33579,10 +33582,10 @@ property_value: MassAvg "197.24" xsd:float
 property_value: MassMono "197.116427" xsd:float
 property_value: Origin "C, K" xsd:string
 property_value: Source "hypothetical" xsd:string
-is_a: MOD:00692
-is_a: MOD:02044
-is_a: MOD:02051
-is_a: MOD:01853
+is_a: MOD:00692 ! uncategorized crosslinked residues
+is_a: MOD:02044 ! crosslinked L-cysteine residue
+is_a: MOD:02051 ! crosslinked L-lysine residue
+is_a: MOD:01853 ! L-lysinoalanine
 
 [Term]
 id: MOD:01853
@@ -33590,28 +33593,28 @@ name: L-lysinoalanine
 def: "A protein modification that effectively converts an L-lysine residue to L-lysinoalanine either by forming a cross-link with peptidyl-cysteine or peptidyl-serine, or by condensation with free serine." [PubMed:18688235]
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00859
-is_a: MOD:00912
+is_a: MOD:00859 ! modified residue that can arise from different natural residues
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:01854
 name: sulfur monooxygenated residue
 def: "A protein modification that effectively adds one oxygen atom to a sulfur atom of a residue without removing hydrogen atoms." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00680
+is_a: MOD:00680 ! sulfur oxygenated residue
 
 [Term]
 id: MOD:01855
 name: sulfur dioxygenated residue
 def: "A protein modification that effectively adds two oxygen atoms to a sulfur atom of a residue without removing hydrogen atoms." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:00680
+is_a: MOD:00680 ! sulfur oxygenated residue
 
 [Term]
 id: MOD:01856
 name: oxazole/oxazoline ring crosslinked residues (Cys)
 def: "A protein modification that crosslinks two residues by rearrangement and condensation of a cysteine with the carbonyl of the preceding residue to form a 1,3-oxazole-4-carbothionic acid." [PubMed:18688235]
-is_a: MOD:01419
+is_a: MOD:01419 ! oxazole/oxazoline ring crosslinked residues
 
 [Term]
 id: MOD:01857
@@ -33630,9 +33633,9 @@ property_value: MassMono "232.034020" xsd:float
 property_value: Origin "C, M" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0495
-is_a: MOD:02044
-is_a: MOD:02052
-is_a: MOD:01992
+is_a: MOD:02044 ! crosslinked L-cysteine residue
+is_a: MOD:02052 ! crosslinked L-methionine residue
+is_a: MOD:01992 ! alpha-carbon thioether crosslinked residues
 
 [Term]
 id: MOD:01858
@@ -33652,9 +33655,9 @@ property_value: MassMono "306.088557" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0628
-is_a: MOD:00426
-is_a: MOD:00448
-is_a: MOD:00905
+is_a: MOD:00426 ! S-glycosylated residue
+is_a: MOD:00448 ! mono-N-acetylaminoglucosylated residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:01859
@@ -33678,9 +33681,9 @@ property_value: MassMono "248.061949" xsd:float
 property_value: Origin "C, F" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: uniprot.ptm:PTM-0451
-is_a: MOD:02044
-is_a: MOD:02053
-is_a: MOD:01861
+is_a: MOD:02044 ! crosslinked L-cysteine residue
+is_a: MOD:02053 ! crosslinked L-phenylalanine residue
+is_a: MOD:01861 ! isothiazolidinone ring crosslinked residues
 
 [Term]
 id: MOD:01860
@@ -33699,15 +33702,15 @@ property_value: MassMono "499.093051" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0452
-is_a: MOD:00905
-is_a: MOD:01862
+is_a: MOD:00905 ! modified L-cysteine residue
+is_a: MOD:01862 ! disulfide conjugated residue
 
 [Term]
 id: MOD:01861
 name: isothiazolidinone ring crosslinked residues
 def: "A protein modification that crosslinks two residues by condensation of a cysteine thiol with the amido nitrogen of the following residue to form an isothiazolidinone ring." [PubMed:18688235]
 comment: The isothiazolidinone ring is usually formed by the reaction of a cysteine sulfenic acid with the amido nitrogen releasing water.
-is_a: MOD:00033
+is_a: MOD:00033 ! crosslinked residues
 
 [Term]
 id: MOD:01862
@@ -33716,7 +33719,7 @@ def: "A protein modification that effectively replaces the hydrogen atom of a cy
 subset: PSI-MOD-slim
 synonym: "S-thiolation" EXACT PSI-MOD-alternate []
 property_value: Origin "C" xsd:string
-is_a: MOD:01886
+is_a: MOD:01886 ! thiolated residue
 
 [Term]
 id: MOD:01863
@@ -33728,8 +33731,8 @@ synonym: "(4-methylpiperazin-1-yl)acetyl" EXACT PSI-MOD-alternate []
 synonym: "Applied Biosystems mTRAQ(TM) reagent" RELATED Unimod-alternate []
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01426
-is_a: MOD:01705
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
+is_a: MOD:01705 ! isotope tagged reagent acylated residue
 
 [Term]
 id: MOD:01864
@@ -33746,8 +33749,8 @@ property_value: DiffMono "140.094963" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:888
-is_a: MOD:01863
-is_a: MOD:01868
+is_a: MOD:01863 ! mTRAQ reporter+balance reagent acylated residue
+is_a: MOD:01868 ! modifications with monoisotopic mass differences that are nominally equal at 140.094963 Da
 
 [Term]
 id: MOD:01865
@@ -33766,7 +33769,7 @@ property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:888
-is_a: MOD:01864
+is_a: MOD:01864 ! mTRAQ light reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01866
@@ -33787,8 +33790,8 @@ property_value: MassMono "268.189926" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:888
-is_a: MOD:01864
-is_a: MOD:01875
+is_a: MOD:01864 ! mTRAQ light reporter+balance reagent acylated residue
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01867
@@ -33808,15 +33811,15 @@ property_value: MassMono "303.158292" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:888
-is_a: MOD:00919
-is_a: MOD:01864
+is_a: MOD:00919 ! modified L-tyrosine residue
+is_a: MOD:01864 ! mTRAQ light reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01868
 name: modifications with monoisotopic mass differences that are nominally equal at 140.094963 Da
 def: "Modifications that have monoisotopic mass differences from their respective origins of 140.094963 Da." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:01515
+is_a: MOD:01515 ! modifications with monoisotopic mass differences that are nominally equal at a resolution below 0.000001 Da
 
 [Term]
 id: MOD:01869
@@ -33830,15 +33833,15 @@ property_value: MassAvg "113.11" xsd:float
 property_value: MassMono "113.107325" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01870
-relationship: derives_from MOD:01864
+is_a: MOD:01870 ! mTRAQ reporter fragment
+relationship: derives_from MOD:01864 ! mTRAQ light reporter+balance reagent acylated residue
 
 [Term]
 id: MOD:01870
 name: mTRAQ reporter fragment
 def: "A protein modification reporter fragment produced by an Applied Biosystems mTRAQ reagent derivatized residue." [PubMed:18688235]
 subset: PSI-MOD-slim
-is_a: MOD:01520
+is_a: MOD:01520 ! modification reporter fragment
 
 [Term]
 id: MOD:01871
@@ -33860,9 +33863,9 @@ property_value: Origin "MOD:01060" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:26
-is_a: MOD:01160
-relationship: contains MOD:00419
-relationship: derives_from MOD:01060
+is_a: MOD:01160 ! deaminated residue
+relationship: contains MOD:00419 ! (R)-5-oxo-1,4-tetrahydrothiazine-3-carboxylic acid
+relationship: derives_from MOD:01060 ! S-carboxamidomethyl-L-cysteine
 
 [Term]
 id: MOD:01872
@@ -33885,9 +33888,9 @@ property_value: Origin "MOD:01061" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:26
-is_a: MOD:00704
-relationship: contains MOD:00419
-relationship: derives_from MOD:01061
+is_a: MOD:00704 ! dehydrated residue
+relationship: contains MOD:00419 ! (R)-5-oxo-1,4-tetrahydrothiazine-3-carboxylic acid
+relationship: derives_from MOD:01061 ! S-carboxymethyl-L-cysteine
 
 [Term]
 id: MOD:01873
@@ -33906,8 +33909,8 @@ property_value: MassMono "116.034768" xsd:float
 property_value: Origin "A" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00901
-is_a: MOD:01152
+is_a: MOD:00901 ! modified L-alanine residue
+is_a: MOD:01152 ! carboxylated residue
 
 [Term]
 id: MOD:01874
@@ -33926,8 +33929,8 @@ property_value: MassMono "144.066068" xsd:float
 property_value: Origin "V" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00920
-is_a: MOD:01152
+is_a: MOD:00920 ! modified L-valine residue
+is_a: MOD:01152 ! carboxylated residue
 
 [Term]
 id: MOD:01875
@@ -33937,8 +33940,8 @@ subset: PSI-MOD-slim
 synonym: "N6AcylLys" EXACT PSI-MOD-label []
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00670
-is_a: MOD:00912
+is_a: MOD:00670 ! N-acylated residue
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:01876
@@ -33973,9 +33976,9 @@ property_value: Origin "C, R" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0457
-is_a: MOD:02041
-is_a: MOD:02044
-is_a: MOD:01883
+is_a: MOD:02041 ! crosslinked L-arginine residue
+is_a: MOD:02044 ! crosslinked L-cysteine residue
+is_a: MOD:01883 ! 5-imidazolinone ring crosslinked residues (Cys)
 
 [Term]
 id: MOD:01878
@@ -33995,9 +33998,9 @@ property_value: MassMono "200.025563" xsd:float
 property_value: Origin "C, T" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0458
-is_a: MOD:02044
-is_a: MOD:02056
-is_a: MOD:01856
+is_a: MOD:02044 ! crosslinked L-cysteine residue
+is_a: MOD:02056 ! crosslinked L-threonine residue
+is_a: MOD:01856 ! oxazole/oxazoline ring crosslinked residues (Cys)
 
 [Term]
 id: MOD:01879
@@ -34016,8 +34019,8 @@ property_value: MassMono "289.875530" xsd:float
 property_value: Origin "C, C, R, T" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00742
-is_a: MOD:02067
+is_a: MOD:00742 ! copper containing modified residue
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
 
 [Term]
 id: MOD:01880
@@ -34037,8 +34040,8 @@ property_value: MassMono "199.168462" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0684
-is_a: MOD:00912
-is_a: MOD:01884
+is_a: MOD:00912 ! modified L-lysine residue
+is_a: MOD:01884 ! 4-aminobutylated residue
 
 [Term]
 id: MOD:01881
@@ -34056,21 +34059,21 @@ property_value: MassAvg "244.29" xsd:float
 property_value: MassMono "244.121178" xsd:float
 property_value: Origin "F, V" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00692
-is_a: MOD:02053
-is_a: MOD:02059
+is_a: MOD:00692 ! uncategorized crosslinked residues
+is_a: MOD:02053 ! crosslinked L-phenylalanine residue
+is_a: MOD:02059 ! crosslinked L-valine residue
 
 [Term]
 id: MOD:01882
 name: 5-imidazolinone ring crosslinked residues (Gly)
 def: "A protein modification that effectively crosslinks the carbonyl of an amino acid residue at position n with the alpha amino of a glycine residue at position n+2 to form a 5-imidazolinone ring." [PubMed:18688235]
-is_a: MOD:00691
+is_a: MOD:00691 ! 5-imidazolinone ring crosslinked residues
 
 [Term]
 id: MOD:01883
 name: 5-imidazolinone ring crosslinked residues (Cys)
 def: "A protein modification that crosslinks two residues by rearrangement and condensation of a cysteine with the carbonyl of the preceding residue to form a 5-imidazolinone ring." [PubMed:18688235]
-is_a: MOD:00691
+is_a: MOD:00691 ! 5-imidazolinone ring crosslinked residues
 
 [Term]
 id: MOD:01884
@@ -34078,7 +34081,7 @@ name: 4-aminobutylated residue
 def: "A protein modification that effectively replaces a hydrogen atom with a 4-aminobutyl group, usually derived from spermidine." [PubMed:18688235]
 subset: PSI-MOD-slim
 property_value: Origin "X" xsd:string
-is_a: MOD:00001
+is_a: MOD:00001 ! alkylated residue
 
 [Term]
 id: MOD:01885
@@ -34093,7 +34096,7 @@ property_value: DiffFormula "C 10 H 14 N 2 O 2 S 1" xsd:string
 property_value: DiffMono "226.077599" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00649
+is_a: MOD:00649 ! acylated residue
 
 [Term]
 id: MOD:01886
@@ -34101,7 +34104,7 @@ name: thiolated residue
 def: "A protein modification that effectively replaces a hydrogen atom with an sulfanyl or substituted sulfanyl group." [PubMed:18688235]
 subset: PSI-MOD-slim
 property_value: Origin "X" xsd:string
-is_a: MOD:00860
+is_a: MOD:00860 ! sulfur containing modified residue
 
 [Term]
 id: MOD:01887
@@ -34120,8 +34123,8 @@ property_value: MassAvg "612.67" xsd:float
 property_value: MassMono "612.134856" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00912
-is_a: MOD:01659
+is_a: MOD:00912 ! modified L-lysine residue
+is_a: MOD:01659 ! Uniblue A derivatized residue
 
 [Term]
 id: MOD:01888
@@ -34134,7 +34137,7 @@ property_value: DiffFormula "C 0 H -2 N 0 O 0" xsd:string
 property_value: DiffMono "-2.015650" xsd:float
 property_value: Origin "X" xsd:string
 xref: Unimod:401
-is_a: MOD:00683
+is_a: MOD:00683 ! dehydrogenated residue
 
 [Term]
 id: MOD:01889
@@ -34159,8 +34162,8 @@ property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:957
 xref: uniprot.ptm:PTM-0674
-is_a: MOD:00001
-is_a: MOD:00905
+is_a: MOD:00001 ! alkylated residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:01890
@@ -34178,8 +34181,8 @@ property_value: MassMono "281.107222" xsd:float
 property_value: Origin "H, MOD:00030" xsd:string
 property_value: Source "hypothetical" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:02048
-is_a: MOD:02062
+is_a: MOD:02048 ! crosslinked L-histidine residue
+is_a: MOD:02062 ! crosslinked N-formyl-L-methionine residue
 
 [Term]
 id: MOD:01891
@@ -34197,8 +34200,8 @@ property_value: MassMono "281.107222" xsd:float
 property_value: Origin "H, M" xsd:string
 property_value: Source "hypothetical" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:02048
-is_a: MOD:02052
+is_a: MOD:02048 ! crosslinked L-histidine residue
+is_a: MOD:02052 ! crosslinked L-methionine residue
 
 [Term]
 id: MOD:01892
@@ -34223,7 +34226,7 @@ property_value: MassMono "196.121178" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: uniprot.ptm:PTM-0475
-is_a: MOD:01875
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01893
@@ -34246,7 +34249,7 @@ property_value: MassMono "214.095357" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: uniprot.ptm:PTM-0467
-is_a: MOD:01875
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01894
@@ -34260,7 +34263,7 @@ property_value: DiffMono "56.026215" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:58
-is_a: MOD:00649
+is_a: MOD:00649 ! acylated residue
 
 [Term]
 id: MOD:01895
@@ -34274,8 +34277,8 @@ property_value: DiffMono "56.026215" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:58
-relationship: derives_from MOD:00451
-is_a: MOD:01426
+relationship: derives_from MOD:00451 ! alpha-amino propanoylated residue
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
 
 [Term]
 id: MOD:01896
@@ -34288,8 +34291,8 @@ property_value: DiffFormula "C 2 F 3 H 1 O 2" xsd:string
 property_value: DiffMono "113.992864" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00498
-is_a: MOD:00848
+is_a: MOD:00498 ! fluorinated residue
+is_a: MOD:00848 ! reagent derivatized residue
 
 [Term]
 id: MOD:01897
@@ -34310,10 +34313,10 @@ property_value: MassMono "127.063329" xsd:float
 property_value: Origin "I" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0466
-is_a: MOD:00601
-is_a: MOD:00679
-is_a: MOD:00910
-is_a: MOD:01905
+is_a: MOD:00601 ! cyclized residue
+is_a: MOD:00679 ! carbon oxygenated residue
+is_a: MOD:00910 ! modified L-isoleucine residue
+is_a: MOD:01905 ! 5-hydroxy-3-methyl-L-proline
 
 [Term]
 id: MOD:01898
@@ -34335,7 +34338,7 @@ property_value: Origin "R" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0459
-is_a: MOD:00783
+is_a: MOD:00783 ! dimethylated L-arginine
 
 [Term]
 id: MOD:01899
@@ -34354,9 +34357,9 @@ property_value: MassMono "239.084081" xsd:float
 property_value: Origin "C, R" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0460
-is_a: MOD:02041
-is_a: MOD:01420
-is_a: MOD:02082
+is_a: MOD:02041 ! crosslinked L-arginine residue
+is_a: MOD:01420 ! thiazole/thiazoline ring crosslinked residues
+is_a: MOD:02082 ! didehydrogenated and dehydrated residue
 
 [Term]
 id: MOD:01900
@@ -34376,9 +34379,9 @@ property_value: MassMono "184.030649" xsd:float
 property_value: Origin "C, T" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0461
-is_a: MOD:02044
-is_a: MOD:01422
-is_a: MOD:02082
+is_a: MOD:02044 ! crosslinked L-cysteine residue
+is_a: MOD:01422 ! oxazole/oxazoline ring crosslinked residues (Thr)
+is_a: MOD:02082 ! didehydrogenated and dehydrated residue
 
 [Term]
 id: MOD:01901
@@ -34398,8 +34401,8 @@ property_value: MassMono "182.069142" xsd:float
 property_value: Origin "T, T" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0462
-is_a: MOD:01422
-is_a: MOD:02082
+is_a: MOD:01422 ! oxazole/oxazoline ring crosslinked residues (Thr)
+is_a: MOD:02082 ! didehydrogenated and dehydrated residue
 
 [Term]
 id: MOD:01902
@@ -34419,9 +34422,9 @@ property_value: MassMono "180.089878" xsd:float
 property_value: Origin "I, S" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0463
-is_a: MOD:02049
-is_a: MOD:01421
-is_a: MOD:02082
+is_a: MOD:02049 ! crosslinked L-isoleucine residue
+is_a: MOD:01421 ! oxazole/oxazoline ring crosslinked residues (Ser)
+is_a: MOD:02082 ! didehydrogenated and dehydrated residue
 
 [Term]
 id: MOD:01903
@@ -34441,8 +34444,8 @@ property_value: MassMono "154.037842" xsd:float
 property_value: Origin "S, S" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0464
-is_a: MOD:01421
-is_a: MOD:02082
+is_a: MOD:01421 ! oxazole/oxazoline ring crosslinked residues (Ser)
+is_a: MOD:02082 ! didehydrogenated and dehydrated residue
 
 [Term]
 id: MOD:01904
@@ -34463,9 +34466,9 @@ property_value: MassMono "170.069142" xsd:float
 property_value: Origin "S, T" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0465
-is_a: MOD:02055
-is_a: MOD:01422
-is_a: MOD:00954
+is_a: MOD:02055 ! crosslinked L-serine residue
+is_a: MOD:01422 ! oxazole/oxazoline ring crosslinked residues (Thr)
+is_a: MOD:00954 ! crosslinked residues with loss of water
 
 [Term]
 id: MOD:01905
@@ -34482,8 +34485,8 @@ property_value: MassAvg "127.14" xsd:float
 property_value: MassMono "127.063329" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00859
-relationship: has_functional_parent MOD:01024
+is_a: MOD:00859 ! modified residue that can arise from different natural residues
+relationship: has_functional_parent MOD:01024 ! monohydroxylated proline
 
 [Term]
 id: MOD:01906
@@ -34501,8 +34504,8 @@ property_value: MassMono "131.039936" xsd:float
 property_value: Origin "M" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00601
-is_a: MOD:00913
+is_a: MOD:00601 ! cyclized residue
+is_a: MOD:00913 ! modified L-methionine residue
 
 [Term]
 id: MOD:01907
@@ -34521,9 +34524,9 @@ property_value: MassMono "131.039936" xsd:float
 property_value: Origin "MOD:001464" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00601
-is_a: MOD:00913
-relationship: derives_from MOD:01464
+is_a: MOD:00601 ! cyclized residue
+is_a: MOD:00913 ! modified L-methionine residue
+relationship: derives_from MOD:01464 ! protonated L-methionine (L-methioninium) residue
 
 [Term]
 id: MOD:01908
@@ -34538,7 +34541,7 @@ property_value: DiffMono "214.971085" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:261
-is_a: MOD:00584
+is_a: MOD:00584 ! 4-sulfophenyl isothiocyanate derivatized residue
 
 [Term]
 id: MOD:01909
@@ -34552,7 +34555,7 @@ property_value: DiffMono "220.991214" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:464
-is_a: MOD:00880
+is_a: MOD:00880 ! 6x(13)C labeled 4-sulfophenyl isothiocyanate derivatized residue
 
 [Term]
 id: MOD:01910
@@ -34565,7 +34568,7 @@ property_value: DiffMono "17.990578" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:127
-is_a: MOD:00498
+is_a: MOD:00498 ! fluorinated residue
 
 [Term]
 id: MOD:01911
@@ -34578,7 +34581,7 @@ property_value: DiffMono "33.961028" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:936
-is_a: MOD:00753
+is_a: MOD:00753 ! chlorinated residue
 
 [Term]
 id: MOD:01912
@@ -34591,7 +34594,7 @@ property_value: DiffMono "77.910512" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 xref: Unimod:340
-is_a: MOD:00754
+is_a: MOD:00754 ! brominated residue
 
 [Term]
 id: MOD:01913
@@ -34606,8 +34609,8 @@ property_value: MassAvg "220.66" xsd:float
 property_value: MassMono "220.040341" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01068
-is_a: MOD:01911
+is_a: MOD:01068 ! halogenated tryptophan
+is_a: MOD:01911 ! monochlorinated residue
 
 [Term]
 id: MOD:01914
@@ -34628,8 +34631,8 @@ property_value: Origin "MOD:00037" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:907
 xref: uniprot.ptm:PTM-0556
-is_a: MOD:00476
-is_a: MOD:00396
+is_a: MOD:00476 ! monogalactosylated residue
+is_a: MOD:00396 ! O-glycosylated residue
 
 [Term]
 id: MOD:01915
@@ -34648,8 +34651,8 @@ property_value: MassMono "100.039853" xsd:float
 property_value: Origin "A" xsd:string
 property_value: Source "hypothetical" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00409
-is_a: MOD:00901
+is_a: MOD:00409 ! N-formylated residue
+is_a: MOD:00901 ! modified L-alanine residue
 
 [Term]
 id: MOD:01916
@@ -34670,8 +34673,8 @@ property_value: MassMono "366.142701" xsd:float
 property_value: Origin "Y" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0570
-is_a: MOD:00563
-is_a: MOD:01927
+is_a: MOD:00563 ! mono-N-acetylaminogalactosylated residue
+is_a: MOD:01927 ! O-glycosyl-L-tyrosine
 
 [Term]
 id: MOD:01917
@@ -34694,9 +34697,9 @@ property_value: MassMono "225.111341" xsd:float
 property_value: Origin "D, K" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0486
-is_a: MOD:02043
-is_a: MOD:01929
-is_a: MOD:00954
+is_a: MOD:02043 ! crosslinked L-aspartic acid residue
+is_a: MOD:01929 ! N6-(L-isoaspartyl)-L-lysine
+is_a: MOD:00954 ! crosslinked residues with loss of water
 
 [Term]
 id: MOD:01918
@@ -34720,7 +34723,7 @@ property_value: MassMono "144.089878" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0472
-is_a: MOD:00037
+is_a: MOD:00037 ! 5-hydroxy-L-lysine
 
 [Term]
 id: MOD:01919
@@ -34745,7 +34748,7 @@ property_value: MassMono "131.021858" xsd:float
 property_value: Origin "D" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0473
-is_a: MOD:01926
+is_a: MOD:01926 ! 3-hydroxy-L-aspartic acid
 
 [Term]
 id: MOD:01920
@@ -34763,8 +34766,8 @@ property_value: MassMono "153.053826" xsd:float
 property_value: Origin "H" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0477
-is_a: MOD:00909
-is_a: MOD:00677
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:00677 ! hydroxylated residue
 
 [Term]
 id: MOD:01921
@@ -34782,8 +34785,8 @@ property_value: MassAvg "115.09" xsd:float
 property_value: MassMono "115.026943" xsd:float
 property_value: Origin "D" xsd:string
 property_value: Source "artifactual" xsd:string
-is_a: MOD:00904
-is_a: MOD:01942
+is_a: MOD:00904 ! modified L-aspartic acid residue
+is_a: MOD:01942 ! D-aspartic acid
 
 [Term]
 id: MOD:01922
@@ -34800,8 +34803,8 @@ property_value: MassAvg "99.09" xsd:float
 property_value: MassMono "99.032028" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00916
-relationship: has_functional_parent MOD:00189
+is_a: MOD:00916 ! modified L-serine residue
+relationship: has_functional_parent MOD:00189 ! dehydroalanine (Ser)
 
 [Term]
 id: MOD:01923
@@ -34823,10 +34826,10 @@ property_value: MassMono "242.114081" xsd:float
 property_value: Origin "D, K" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
-is_a: MOD:00688
-is_a: MOD:02043
-is_a: MOD:00954
-is_a: MOD:01875
+is_a: MOD:00688 ! isopeptide crosslinked residues
+is_a: MOD:02043 ! crosslinked L-aspartic acid residue
+is_a: MOD:00954 ! crosslinked residues with loss of water
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01924
@@ -34845,9 +34848,9 @@ property_value: MassAvg "229.34" xsd:float
 property_value: MassMono "229.113650" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00666
-is_a: MOD:00672
-is_a: MOD:00905
+is_a: MOD:00666 ! octanoylated residue
+is_a: MOD:00672 ! S-acylated residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:01925
@@ -34872,7 +34875,7 @@ property_value: MassMono "144.089878" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0471
-is_a: MOD:00037
+is_a: MOD:00037 ! 5-hydroxy-L-lysine
 
 [Term]
 id: MOD:01926
@@ -34895,8 +34898,8 @@ property_value: MassMono "131.021858" xsd:float
 property_value: Origin "D" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:35
-is_a: MOD:00425
-is_a: MOD:00904
+is_a: MOD:00425 ! monohydroxylated residue
+is_a: MOD:00904 ! modified L-aspartic acid residue
 
 [Term]
 id: MOD:01927
@@ -34906,8 +34909,8 @@ subset: PSI-MOD-slim
 synonym: "OGlycoTyr" EXACT PSI-MOD-label []
 property_value: Origin "Y" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00396
-is_a: MOD:00919
+is_a: MOD:00396 ! O-glycosylated residue
+is_a: MOD:00919 ! modified L-tyrosine residue
 
 [Term]
 id: MOD:01928
@@ -34927,8 +34930,8 @@ property_value: MassMono "155.045667" xsd:float
 property_value: Origin "G" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00688
-is_a: MOD:02047
+is_a: MOD:00688 ! isopeptide crosslinked residues
+is_a: MOD:02047 ! crosslinked glycine residue
 
 [Term]
 id: MOD:01929
@@ -34948,8 +34951,8 @@ property_value: MassAvg "225.25" xsd:float
 property_value: MassMono "225.111341" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00688
-is_a: MOD:01875
+is_a: MOD:00688 ! isopeptide crosslinked residues
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01930
@@ -34967,8 +34970,8 @@ property_value: MassAvg "115.09" xsd:float
 property_value: MassMono "115.026943" xsd:float
 property_value: Origin "N" xsd:string
 property_value: Source "artifactual" xsd:string
-is_a: MOD:00903
-is_a: MOD:01942
+is_a: MOD:00903 ! modified L-asparagine residue
+is_a: MOD:01942 ! D-aspartic acid
 
 [Term]
 id: MOD:01931
@@ -34991,8 +34994,8 @@ property_value: MassAvg "208.15" xsd:float
 property_value: MassMono "208.061294" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "hypothetical" xsd:string
-is_a: MOD:00912
-is_a: MOD:01456
+is_a: MOD:00912 ! modified L-lysine residue
+is_a: MOD:01456 ! N-phosphorylated residue
 
 [Term]
 id: MOD:01932
@@ -35015,8 +35018,8 @@ property_value: MassAvg "239.32" xsd:float
 property_value: MassMono "239.163377" xsd:float
 property_value: Origin "K, K" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:02051
-is_a: MOD:00946
+is_a: MOD:02051 ! crosslinked L-lysine residue
+is_a: MOD:00946 ! crosslinked residues with loss of ammonia
 
 [Term]
 id: MOD:01933
@@ -35035,8 +35038,8 @@ property_value: MassAvg "454.55" xsd:float
 property_value: MassMono "454.244881" xsd:float
 property_value: Origin "K, K, K, K" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:02051
-is_a: MOD:01425
+is_a: MOD:02051 ! crosslinked L-lysine residue
+is_a: MOD:01425 ! pyridinyl ring crosslinked residues
 
 [Term]
 id: MOD:01934
@@ -35055,8 +35058,8 @@ property_value: MassAvg "454.55" xsd:float
 property_value: MassMono "454.244881" xsd:float
 property_value: Origin "K, K, K, K" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:02051
-is_a: MOD:01425
+is_a: MOD:02051 ! crosslinked L-lysine residue
+is_a: MOD:01425 ! pyridinyl ring crosslinked residues
 
 [Term]
 id: MOD:01935
@@ -35074,9 +35077,9 @@ property_value: MassMono "306.142701" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0572
-relationship: derives_from MOD:01047
-is_a: MOD:00396
-is_a: MOD:00912
+relationship: derives_from MOD:01047 ! monohydroxylated lysine
+is_a: MOD:00396 ! O-glycosylated residue
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:01936
@@ -35093,8 +35096,8 @@ property_value: MassAvg "392.63" xsd:float
 property_value: MassMono "392.340279" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:01875
-is_a: MOD:02011
+is_a: MOD:01875 ! N6-acylated L-lysine
+is_a: MOD:02011 ! N-oleoylated residue
 
 [Term]
 id: MOD:01937
@@ -35114,8 +35117,8 @@ property_value: MassMono "370.277976" xsd:float
 property_value: Origin "M" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00913
-is_a: MOD:01685
+is_a: MOD:00913 ! modified L-methionine residue
+is_a: MOD:01685 ! alpha-amino palmitoylated residue
 
 [Term]
 id: MOD:01938
@@ -35133,9 +35136,9 @@ property_value: MassAvg "200.21" xsd:float
 property_value: MassMono "200.025563" xsd:float
 property_value: Origin "C, N" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:02042
-is_a: MOD:01945
-is_a: MOD:00946
+is_a: MOD:02042 ! crosslinked L-asparagine residue
+is_a: MOD:01945 ! 2-(2-aminosuccinimidyl)-3-sulfanylpropanoic acid
+is_a: MOD:00946 ! crosslinked residues with loss of ammonia
 
 [Term]
 id: MOD:01939
@@ -35153,9 +35156,9 @@ property_value: MassAvg "200.21" xsd:float
 property_value: MassMono "200.025563" xsd:float
 property_value: Origin "C, D" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:02043
-is_a: MOD:01945
-is_a: MOD:00954
+is_a: MOD:02043 ! crosslinked L-aspartic acid residue
+is_a: MOD:01945 ! 2-(2-aminosuccinimidyl)-3-sulfanylpropanoic acid
+is_a: MOD:00954 ! crosslinked residues with loss of water
 
 [Term]
 id: MOD:01940
@@ -35173,9 +35176,9 @@ property_value: MassAvg "226.19" xsd:float
 property_value: MassMono "226.058971" xsd:float
 property_value: Origin "E, N" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:02042
-is_a: MOD:01946
-is_a: MOD:00946
+is_a: MOD:02042 ! crosslinked L-asparagine residue
+is_a: MOD:01946 ! 2-(2-aminosuccinimidyl)pentanedioic acid
+is_a: MOD:00946 ! crosslinked residues with loss of ammonia
 
 [Term]
 id: MOD:01941
@@ -35193,9 +35196,9 @@ property_value: MassAvg "226.19" xsd:float
 property_value: MassMono "226.058971" xsd:float
 property_value: Origin "D, E" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:02043
-is_a: MOD:01946
-is_a: MOD:00954
+is_a: MOD:02043 ! crosslinked L-aspartic acid residue
+is_a: MOD:01946 ! 2-(2-aminosuccinimidyl)pentanedioic acid
+is_a: MOD:00954 ! crosslinked residues with loss of water
 
 [Term]
 id: MOD:01942
@@ -35210,14 +35213,14 @@ property_value: MassAvg "115.09" xsd:float
 property_value: MassMono "115.026943" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifactual" xsd:string
-is_a: MOD:00664
-is_a: MOD:00859
+is_a: MOD:00664 ! stereoisomerized residue
+is_a: MOD:00859 ! modified residue that can arise from different natural residues
 
 [Term]
 id: MOD:01943
 name: pyrrolidione ring crosslinked residues
 def: "A protein modification that crosslinks two adjacent residues by formation of a pyrrolidione ring." [PubMed:18688235]
-is_a: MOD:00033
+is_a: MOD:00033 ! crosslinked residues
 
 [Term]
 id: MOD:01944
@@ -35227,8 +35230,8 @@ comment: Cross-link 2; this cross-link is formed by the condensation of an aspar
 subset: PSI-MOD-slim
 property_value: Origin "X" xsd:string
 property_value: Source "hypothetical" xsd:string
-is_a: MOD:00033
-is_a: MOD:00859
+is_a: MOD:00033 ! crosslinked residues
+is_a: MOD:00859 ! modified residue that can arise from different natural residues
 
 [Term]
 id: MOD:01945
@@ -35240,8 +35243,8 @@ property_value: MassAvg "154.13" xsd:float
 property_value: MassMono "154.037842" xsd:float
 property_value: Origin "C, X" xsd:string
 property_value: Source "hypothetical" xsd:string
-is_a: MOD:02044
-is_a: MOD:01944
+is_a: MOD:02044 ! crosslinked L-cysteine residue
+is_a: MOD:01944 ! 2-aminosuccinimide ring crosslinked residues
 
 [Term]
 id: MOD:01946
@@ -35253,8 +35256,8 @@ property_value: MassAvg "154.13" xsd:float
 property_value: MassMono "154.037842" xsd:float
 property_value: Origin "E, X" xsd:string
 property_value: Source "hypothetical" xsd:string
-is_a: MOD:02045
-is_a: MOD:01944
+is_a: MOD:02045 ! crosslinked L-glutamic acid residue
+is_a: MOD:01944 ! 2-aminosuccinimide ring crosslinked residues
 
 [Term]
 id: MOD:01947
@@ -35275,10 +35278,10 @@ property_value: MassAvg "198.18" xsd:float
 property_value: MassMono "198.064057" xsd:float
 property_value: Origin "D, T" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00885
-is_a: MOD:02043
-is_a: MOD:00954
-is_a: MOD:01978
+is_a: MOD:00885 ! ester crosslinked residues
+is_a: MOD:02043 ! crosslinked L-aspartic acid residue
+is_a: MOD:00954 ! crosslinked residues with loss of water
+is_a: MOD:01978 ! O-(L-isoaspartyl)-L-threonine
 
 [Term]
 id: MOD:01948
@@ -35297,8 +35300,8 @@ property_value: MassAvg "241.26" xsd:float
 property_value: MassMono "241.052112" xsd:float
 property_value: Origin "C, S, S" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:02055
-is_a: MOD:01993
+is_a: MOD:02055 ! crosslinked L-serine residue
+is_a: MOD:01993 ! beta-carbon thioether crosslinked residues
 
 [Term]
 id: MOD:01949
@@ -35317,9 +35320,9 @@ property_value: MassMono "423.158292" xsd:float
 property_value: Origin "F, Y, Y" xsd:string
 property_value: Source "hypothetical" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00033
-is_a: MOD:02053
-is_a: MOD:02058
+is_a: MOD:00033 ! crosslinked residues
+is_a: MOD:02053 ! crosslinked L-phenylalanine residue
+is_a: MOD:02058 ! crosslinked L-tyrosine residue
 
 [Term]
 id: MOD:01950
@@ -35337,7 +35340,7 @@ property_value: MassMono "222.111676" xsd:float
 property_value: Origin "Q" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0488
-is_a: MOD:00907
+is_a: MOD:00907 ! modified L-glutamine residue
 
 [Term]
 id: MOD:01951
@@ -35356,9 +35359,9 @@ property_value: MassAvg "198.18" xsd:float
 property_value: MassMono "198.064057" xsd:float
 property_value: Origin "Q, S" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:02046
-is_a: MOD:00946
-is_a: MOD:01977
+is_a: MOD:02046 ! crosslinked L-glutamine residue
+is_a: MOD:00946 ! crosslinked residues with loss of ammonia
+is_a: MOD:01977 ! O-(L-isoglutamyl)-L-serine
 
 [Term]
 id: MOD:01952
@@ -35379,11 +35382,11 @@ property_value: MassAvg "212.20" xsd:float
 property_value: MassMono "212.079707" xsd:float
 property_value: Origin "Q, T" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:02046
-is_a: MOD:02056
-is_a: MOD:01979
-is_a: MOD:00885
-is_a: MOD:00946
+is_a: MOD:02046 ! crosslinked L-glutamine residue
+is_a: MOD:02056 ! crosslinked L-threonine residue
+is_a: MOD:01979 ! O-(L-isoglutamyl)-L-threonine
+is_a: MOD:00885 ! ester crosslinked residues
+is_a: MOD:00946 ! crosslinked residues with loss of ammonia
 
 [Term]
 id: MOD:01953
@@ -35398,8 +35401,8 @@ property_value: MassAvg "871.95" xsd:float
 property_value: MassMono "871.729098" xsd:float
 property_value: Origin "C, C, C, C" xsd:string
 property_value: Source "hypothetical" xsd:string
-is_a: MOD:00738
-is_a: MOD:02067
+is_a: MOD:00738 ! iron containing modified residue
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
 
 [Term]
 id: MOD:01954
@@ -35420,8 +35423,8 @@ property_value: MassAvg "69.06" xsd:float
 property_value: MassMono "69.021464" xsd:float
 property_value: Origin "U" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:01158
-is_a: MOD:01168
+is_a: MOD:01158 ! modified L-selenocysteine residue
+is_a: MOD:01168 ! dehydroalanine
 
 [Term]
 id: MOD:01955
@@ -35441,12 +35444,12 @@ property_value: MassMono "1175.922825" xsd:float
 property_value: Origin "A, D, D, E, E, E, H" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "C-term" xsd:string
-is_a: MOD:00740
-is_a: MOD:01482
-is_a: MOD:02065
-is_a: MOD:02066
-is_a: MOD:02068
-is_a: MOD:02070
+is_a: MOD:00740 ! manganese containing modified residue
+is_a: MOD:01482 ! calcium containing modified residue
+is_a: MOD:02065 ! metal or metal cluster coordinated L-alanine residue
+is_a: MOD:02066 ! metal or metal cluster coordinated L-aspartic acid residue
+is_a: MOD:02068 ! metal or metal cluster coordinated L-glutamic acid residue
+is_a: MOD:02070 ! metal or metal cluster coordinated L-histidine residue
 
 [Term]
 id: MOD:01956
@@ -35469,7 +35472,7 @@ property_value: MassMono "172.096026" xsd:float
 property_value: Origin "R" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0476
-is_a: MOD:00682
+is_a: MOD:00682 ! hydroxylated arginine
 
 [Term]
 id: MOD:01957
@@ -35489,7 +35492,7 @@ property_value: MassMono "113.047678" xsd:float
 property_value: Origin "P" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: uniprot.ptm:PTM-0668
-is_a: MOD:01024
+is_a: MOD:01024 ! monohydroxylated proline
 
 [Term]
 id: MOD:01958
@@ -35508,8 +35511,8 @@ property_value: MassAvg "992.70" xsd:float
 property_value: MassMono "991.968699" xsd:float
 property_value: Origin "C, C" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00739
-is_a: MOD:02067
+is_a: MOD:00739 ! iron-sulfur cluster containing modification
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
 
 [Term]
 id: MOD:01959
@@ -35526,9 +35529,9 @@ property_value: MassAvg "786.12" xsd:float
 property_value: MassMono "785.666881" xsd:float
 property_value: Origin "C, C, C, E" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00739
-is_a: MOD:02067
-is_a: MOD:02068
+is_a: MOD:00739 ! iron-sulfur cluster containing modification
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
+is_a: MOD:02068 ! metal or metal cluster coordinated L-glutamic acid residue
 
 [Term]
 id: MOD:01960
@@ -35546,9 +35549,9 @@ property_value: MassAvg "785.14" xsd:float
 property_value: MassMono "784.682866" xsd:float
 property_value: Origin "C, C, C, Q" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00739
-is_a: MOD:02067
-is_a: MOD:02069
+is_a: MOD:00739 ! iron-sulfur cluster containing modification
+is_a: MOD:02067 ! metal or metal cluster coordinated L-cysteine residue
+is_a: MOD:02069 ! metal or metal cluster coordinated L-glutamine residue
 
 [Term]
 id: MOD:01961
@@ -35593,7 +35596,7 @@ property_value: MassMono "342.153934" xsd:float
 property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0506
-is_a: MOD:00160
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:01963
@@ -35617,7 +35620,7 @@ property_value: MassMono "315.143035" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0548
-is_a: MOD:00002
+is_a: MOD:00002 ! O-glycosyl-L-serine
 
 [Term]
 id: MOD:01964
@@ -35638,7 +35641,7 @@ property_value: MassMono "361.148515" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0549
-is_a: MOD:00002
+is_a: MOD:00002 ! O-glycosyl-L-serine
 
 [Term]
 id: MOD:01965
@@ -35654,9 +35657,9 @@ property_value: MassAvg "175.13" xsd:float
 property_value: MassMono "175.131068" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "artifact" xsd:string
-relationship: derives_from MOD:00064
-is_a: MOD:01428
-is_a: MOD:01431
+relationship: derives_from MOD:00064 ! N6-acetyl-L-lysine
+is_a: MOD:01428 ! (13)C isotope tagged reagent
+is_a: MOD:01431 ! (2)H deuterium tagged reagent
 
 [Term]
 id: MOD:01966
@@ -35702,8 +35705,8 @@ property_value: MassMono "359.180484" xsd:float
 property_value: Origin "R" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0518
-is_a: MOD:00448
-is_a: MOD:01980
+is_a: MOD:00448 ! mono-N-acetylaminoglucosylated residue
+is_a: MOD:01980 ! omega-N-glycosyl-L-arginine
 
 [Term]
 id: MOD:01968
@@ -35726,7 +35729,7 @@ property_value: MassAvg "186.23" xsd:float
 property_value: MassMono "186.046299" xsd:float
 property_value: Origin "C, T" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:01981
+is_a: MOD:01981 ! 3-methyllanthionine
 
 [Term]
 id: MOD:01969
@@ -35744,8 +35747,8 @@ property_value: MassAvg "392.44" xsd:float
 property_value: MassMono "392.082426" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00860
-is_a: MOD:00905
+is_a: MOD:00860 ! sulfur containing modified residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:01970
@@ -35773,7 +35776,7 @@ property_value: Origin "E" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:450
 xref: uniprot.ptm:PTM-0479
-is_a: MOD:00207
+is_a: MOD:00207 ! L-isoglutamyl-polyglutamic acid
 
 [Term]
 id: MOD:01971
@@ -35797,7 +35800,7 @@ property_value: MassMono "243.121906" xsd:float
 property_value: Origin "E" xsd:string
 property_value: Source "hypothetical" xsd:string
 xref: uniprot.ptm:PTM-0478
-is_a: MOD:00906
+is_a: MOD:00906 ! modified L-glutamic acid residue
 
 [Term]
 id: MOD:01972
@@ -35816,9 +35819,9 @@ property_value: MassAvg "878.63" xsd:float
 property_value: MassMono "878.147237" xsd:float
 property_value: Origin "E" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00860
-is_a: MOD:00861
-is_a: MOD:00906
+is_a: MOD:00860 ! sulfur containing modified residue
+is_a: MOD:00861 ! phosphorus containing modified residue
+is_a: MOD:00906 ! modified L-glutamic acid residue
 
 [Term]
 id: MOD:01973
@@ -35836,8 +35839,8 @@ property_value: MassAvg "296.22" xsd:float
 property_value: MassMono "296.077338" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00861
-is_a: MOD:01875
+is_a: MOD:00861 ! phosphorus containing modified residue
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:01974
@@ -35860,7 +35863,7 @@ property_value: MassMono "146.063411" xsd:float
 property_value: Origin "M" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0636
-is_a: MOD:00716
+is_a: MOD:00716 ! methylated methionine
 
 [Term]
 id: MOD:01975
@@ -35878,8 +35881,8 @@ synonym: "MOD_RES S-poly(beta-hydroxybutyryl)lysine" EXACT UniProt-feature []
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0641
-is_a: MOD:00672
-is_a: MOD:00905
+is_a: MOD:00672 ! S-acylated residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:01976
@@ -35898,8 +35901,8 @@ synonym: "MOD_RES O3-poly(beta-hydroxybutyryl)lysine" EXACT UniProt-feature []
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0640
-is_a: MOD:00671
-is_a: MOD:00916
+is_a: MOD:00671 ! O-acylated residue
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:01977
@@ -35915,9 +35918,9 @@ property_value: MassAvg "198.18" xsd:float
 property_value: MassMono "198.064057" xsd:float
 property_value: Origin "S, X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00859
-is_a: MOD:00885
-is_a: MOD:02055
+is_a: MOD:00859 ! modified residue that can arise from different natural residues
+is_a: MOD:00885 ! ester crosslinked residues
+is_a: MOD:02055 ! crosslinked L-serine residue
 
 [Term]
 id: MOD:01978
@@ -35934,8 +35937,8 @@ property_value: MassAvg "216.19" xsd:float
 property_value: MassMono "216.074621" xsd:float
 property_value: Origin "T, X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00859
-is_a: MOD:02056
+is_a: MOD:00859 ! modified residue that can arise from different natural residues
+is_a: MOD:02056 ! crosslinked L-threonine residue
 
 [Term]
 id: MOD:01979
@@ -35953,8 +35956,8 @@ property_value: MassAvg "230.22" xsd:float
 property_value: MassMono "230.090272" xsd:float
 property_value: Origin "T, X" xsd:string
 property_value: Source "hypothetical" xsd:string
-is_a: MOD:00859
-is_a: MOD:02056
+is_a: MOD:00859 ! modified residue that can arise from different natural residues
+is_a: MOD:02056 ! crosslinked L-threonine residue
 
 [Term]
 id: MOD:01980
@@ -35970,8 +35973,8 @@ synonym: "omega-N-glycosyl-L-arginine" EXACT RESID-alternate []
 property_value: Origin "R" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:41
-is_a: MOD:00006
-is_a: MOD:00902
+is_a: MOD:00006 ! N-glycosylated residue
+is_a: MOD:00902 ! modified L-arginine residue
 
 [Term]
 id: MOD:01981
@@ -35992,9 +35995,9 @@ property_value: MassAvg "186.23" xsd:float
 property_value: MassMono "186.046299" xsd:float
 property_value: Origin "C, T" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:02056
-is_a: MOD:00954
-is_a: MOD:01993
+is_a: MOD:02056 ! crosslinked L-threonine residue
+is_a: MOD:00954 ! crosslinked residues with loss of water
+is_a: MOD:01993 ! beta-carbon thioether crosslinked residues
 
 [Term]
 id: MOD:01982
@@ -36023,8 +36026,8 @@ property_value: Origin "G" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0485
-is_a: MOD:00714
-is_a: MOD:01698
+is_a: MOD:00714 ! methylated glycine
+is_a: MOD:01698 ! alpha-amino trimethylated protonated-residue
 
 [Term]
 id: MOD:01983
@@ -36045,8 +36048,8 @@ property_value: Origin "G" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: uniprot.ptm:PTM-0484
-is_a: MOD:00714
-is_a: MOD:01686
+is_a: MOD:00714 ! methylated glycine
+is_a: MOD:01686 ! alpha-amino dimethylated residue
 
 [Term]
 id: MOD:01984
@@ -36064,8 +36067,8 @@ property_value: MassAvg "172.20" xsd:float
 property_value: MassMono "172.030649" xsd:float
 property_value: Origin "A, C" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:02040
-is_a: MOD:01992
+is_a: MOD:02040 ! crosslinked L-alanine residue
+is_a: MOD:01992 ! alpha-carbon thioether crosslinked residues
 
 [Term]
 id: MOD:01985
@@ -36082,9 +36085,9 @@ property_value: MassAvg "215.23" xsd:float
 property_value: MassMono "215.036462" xsd:float
 property_value: Origin "C, N" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00664
-is_a: MOD:02060
-is_a: MOD:01992
+is_a: MOD:00664 ! stereoisomerized residue
+is_a: MOD:02060 ! crosslinked D-asparagine residue
+is_a: MOD:01992 ! alpha-carbon thioether crosslinked residues
 
 [Term]
 id: MOD:01986
@@ -36101,8 +36104,8 @@ property_value: MassAvg "188.20" xsd:float
 property_value: MassMono "188.025563" xsd:float
 property_value: Origin "C, S" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:02055
-is_a: MOD:01992
+is_a: MOD:02055 ! crosslinked L-serine residue
+is_a: MOD:01992 ! alpha-carbon thioether crosslinked residues
 
 [Term]
 id: MOD:01987
@@ -36119,9 +36122,9 @@ property_value: MassAvg "188.20" xsd:float
 property_value: MassMono "188.025563" xsd:float
 property_value: Origin "C, S" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00664
-is_a: MOD:02064
-is_a: MOD:01992
+is_a: MOD:00664 ! stereoisomerized residue
+is_a: MOD:02064 ! crosslinked D-serine residue
+is_a: MOD:01992 ! alpha-carbon thioether crosslinked residues
 
 [Term]
 id: MOD:01988
@@ -36139,8 +36142,8 @@ property_value: MassAvg "202.23" xsd:float
 property_value: MassMono "202.041213" xsd:float
 property_value: Origin "C, T" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:02056
-is_a: MOD:01992
+is_a: MOD:02056 ! crosslinked L-threonine residue
+is_a: MOD:01992 ! alpha-carbon thioether crosslinked residues
 
 [Term]
 id: MOD:01989
@@ -36158,9 +36161,9 @@ property_value: MassAvg "264.30" xsd:float
 property_value: MassMono "264.056863" xsd:float
 property_value: Origin "C, Y" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00664
-is_a: MOD:02058
-is_a: MOD:01992
+is_a: MOD:00664 ! stereoisomerized residue
+is_a: MOD:02058 ! crosslinked L-tyrosine residue
+is_a: MOD:01992 ! alpha-carbon thioether crosslinked residues
 
 [Term]
 id: MOD:01990
@@ -36177,8 +36180,8 @@ property_value: MassMono "59.036565" xsd:float
 property_value: Origin "G" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:00908
-is_a: MOD:01700
+is_a: MOD:00908 ! modified glycine residue
+is_a: MOD:01700 ! alpha-amino protonated residue
 
 [Term]
 id: MOD:01991
@@ -36197,21 +36200,21 @@ property_value: MassMono "101.083515" xsd:float
 property_value: Origin "MOD:01990" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:01687
-relationship: derives_from MOD:01990
+is_a: MOD:01687 ! alpha-amino trimethylated residue
+relationship: derives_from MOD:01990 ! protonated glycine (glycinium) residue
 
 [Term]
 id: MOD:01992
 name: alpha-carbon thioether crosslinked residues
 def: "A protein modification that crosslinks two residues by formation of a thioether bond between a cysteine thiol and the alpha-carbon of another amino acid residue." [PubMed:18688235]
-is_a: MOD:00687
+is_a: MOD:00687 ! thioether crosslinked residues
 
 [Term]
 id: MOD:01993
 name: beta-carbon thioether crosslinked residues
 def: "A protein modification that crosslinks two residues by formation of a thioether bond between a cysteine thiol and the beta-carbon of another amino acid residue." [PubMed:18688235]
 comment: These are typical lanthionine-like crosslinks.
-is_a: MOD:00687
+is_a: MOD:00687 ! thioether crosslinked residues
 
 [Term]
 id: MOD:01994
@@ -36227,7 +36230,7 @@ property_value: MassAvg "214.22" xsd:float
 property_value: MassMono "214.074228" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "hypothetical" xsd:string
-is_a: MOD:01106
+is_a: MOD:01106 ! N-formyl-L-tryptophan
 
 [Term]
 id: MOD:01995
@@ -36244,7 +36247,7 @@ property_value: MassMono "215.082053" xsd:float
 property_value: Origin "W" xsd:string
 property_value: Source "hypothetical" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:01106
+is_a: MOD:01106 ! N-formyl-L-tryptophan
 
 [Term]
 id: MOD:01996
@@ -36258,7 +36261,7 @@ property_value: DiffAvg "70.09" xsd:float
 property_value: DiffFormula "C 4 H 6 O 1" xsd:string
 property_value: DiffMono "70.041865" xsd:float
 property_value: Origin "X" xsd:string
-is_a: MOD:00649
+is_a: MOD:00649 ! acylated residue
 
 [Term]
 id: MOD:01997
@@ -36273,7 +36276,7 @@ property_value: DiffAvg "70.09" xsd:float
 property_value: DiffFormula "C 4 H 6 N 0 O 1" xsd:string
 property_value: DiffMono "70.041865" xsd:float
 property_value: Origin "X" xsd:string
-is_a: MOD:01996
+is_a: MOD:01996 ! butanoylated residue
 
 [Term]
 id: MOD:01998
@@ -36286,7 +36289,7 @@ property_value: DiffMono "70.041865" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
 property_value: TermSpec "N-term" xsd:string
-is_a: MOD:01997
+is_a: MOD:01997 ! N-butanoylated residue
 
 [Term]
 id: MOD:01999
@@ -36301,7 +36304,7 @@ property_value: MassAvg "394.60" xsd:float
 property_value: MassMono "394.298414" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:02000
+is_a: MOD:02000 ! N6-retinylidene-L-lysine (unspecified geometric isomer)
 
 [Term]
 id: MOD:02000
@@ -36316,7 +36319,7 @@ property_value: MassAvg "394.60" xsd:float
 property_value: MassMono "394.298414" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00912
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:02001
@@ -36328,8 +36331,8 @@ property_value: DiffFormula "C 18 H 34 O 1" xsd:string
 property_value: DiffMono "266.260966" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00649
-is_a: MOD:01155
+is_a: MOD:00649 ! acylated residue
+is_a: MOD:01155 ! lipoconjugated residue
 
 [Term]
 id: MOD:02002
@@ -36341,8 +36344,8 @@ property_value: DiffFormula "C 16 H 28 N 0 O 1" xsd:string
 property_value: DiffMono "236.214016" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00672
-is_a: MOD:01423
+is_a: MOD:00672 ! S-acylated residue
+is_a: MOD:01423 ! palmitoleylated residue
 
 [Term]
 id: MOD:02003
@@ -36351,8 +36354,8 @@ def: "A protein modification that effectively replaces an O3-hydroxy hydrogen at
 subset: PSI-MOD-slim
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00671
-is_a: MOD:00916
+is_a: MOD:00671 ! O-acylated residue
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:02004
@@ -36361,8 +36364,8 @@ def: "A protein modification that effectively replaces an O3-hydroxy hydrogen at
 subset: PSI-MOD-slim
 property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00671
-is_a: MOD:00917
+is_a: MOD:00671 ! O-acylated residue
+is_a: MOD:00917 ! modified L-threonine residue
 
 [Term]
 id: MOD:02005
@@ -36371,8 +36374,8 @@ def: "A protein modification that effectively replaces an sulfanyl hydrogen atom
 subset: PSI-MOD-slim
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00672
-is_a: MOD:00905
+is_a: MOD:00672 ! S-acylated residue
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:02006
@@ -36384,8 +36387,8 @@ property_value: DiffFormula "C 18 H 34 O 1" xsd:string
 property_value: DiffMono "266.260966" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00672
-is_a: MOD:02001
+is_a: MOD:00672 ! S-acylated residue
+is_a: MOD:02001 ! stearoylated residue
 
 [Term]
 id: MOD:02007
@@ -36400,8 +36403,8 @@ property_value: MassAvg "364.58" xsd:float
 property_value: MassMono "364.308979" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:01875
-is_a: MOD:02008
+is_a: MOD:01875 ! N6-acylated L-lysine
+is_a: MOD:02008 ! N-palmitoleylated residue
 
 [Term]
 id: MOD:02008
@@ -36413,8 +36416,8 @@ property_value: DiffFormula "C 16 H 28 N 0 O 1" xsd:string
 property_value: DiffMono "236.214016" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00670
-is_a: MOD:01423
+is_a: MOD:00670 ! N-acylated residue
+is_a: MOD:01423 ! palmitoleylated residue
 
 [Term]
 id: MOD:02009
@@ -36429,8 +36432,8 @@ property_value: MassAvg "394.65" xsd:float
 property_value: MassMono "394.355929" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:01875
-is_a: MOD:02010
+is_a: MOD:01875 ! N6-acylated L-lysine
+is_a: MOD:02010 ! N-stearoylated residue
 
 [Term]
 id: MOD:02010
@@ -36442,8 +36445,8 @@ property_value: DiffFormula "C 18 H 34 O 1" xsd:string
 property_value: DiffMono "266.260966" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00670
-is_a: MOD:02001
+is_a: MOD:00670 ! N-acylated residue
+is_a: MOD:02001 ! stearoylated residue
 
 [Term]
 id: MOD:02011
@@ -36455,8 +36458,8 @@ property_value: DiffFormula "C 18 H 32 N 0 O 1" xsd:string
 property_value: DiffMono "264.245316" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00670
-is_a: MOD:02012
+is_a: MOD:00670 ! N-acylated residue
+is_a: MOD:02012 ! oleoylated residue
 
 [Term]
 id: MOD:02012
@@ -36468,8 +36471,8 @@ property_value: DiffFormula "C 18 H 32 N 0 O 1" xsd:string
 property_value: DiffMono "264.245316" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00649
-is_a: MOD:01155
+is_a: MOD:00649 ! acylated residue
+is_a: MOD:01155 ! lipoconjugated residue
 
 [Term]
 id: MOD:02013
@@ -36484,8 +36487,8 @@ property_value: MassAvg "390.63" xsd:float
 property_value: MassMono "390.324629" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:01875
-is_a: MOD:02014
+is_a: MOD:01875 ! N6-acylated L-lysine
+is_a: MOD:02014 ! N-linoloylated residue
 
 [Term]
 id: MOD:02014
@@ -36497,8 +36500,8 @@ property_value: DiffFormula "C 18 H 30 N 0 O 1" xsd:string
 property_value: DiffMono "262.229666" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00670
-is_a: MOD:02015
+is_a: MOD:00670 ! N-acylated residue
+is_a: MOD:02015 ! linoloylated residue
 
 [Term]
 id: MOD:02015
@@ -36510,8 +36513,8 @@ property_value: DiffFormula "C 18 H 30 N 0 O 1" xsd:string
 property_value: DiffMono "262.229666" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00649
-is_a: MOD:01155
+is_a: MOD:00649 ! acylated residue
+is_a: MOD:01155 ! lipoconjugated residue
 
 [Term]
 id: MOD:02016
@@ -36526,8 +36529,8 @@ property_value: MassAvg "414.67" xsd:float
 property_value: MassMono "414.324629" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:01875
-is_a: MOD:02017
+is_a: MOD:01875 ! N6-acylated L-lysine
+is_a: MOD:02017 ! N-arachidonoylated residue
 
 [Term]
 id: MOD:02017
@@ -36539,8 +36542,8 @@ property_value: DiffFormula "C 20 H 30 N 0 O 1" xsd:string
 property_value: DiffMono "286.229666" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00670
-is_a: MOD:02018
+is_a: MOD:00670 ! N-acylated residue
+is_a: MOD:02018 ! arachidonoylated residue
 
 [Term]
 id: MOD:02018
@@ -36552,8 +36555,8 @@ property_value: DiffFormula "C 20 H 30 N 0 O 1" xsd:string
 property_value: DiffMono "286.229666" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00649
-is_a: MOD:01155
+is_a: MOD:00649 ! acylated residue
+is_a: MOD:01155 ! lipoconjugated residue
 
 [Term]
 id: MOD:02019
@@ -36568,8 +36571,8 @@ property_value: MassAvg "412.66" xsd:float
 property_value: MassMono "412.308979" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:01875
-is_a: MOD:02020
+is_a: MOD:01875 ! N6-acylated L-lysine
+is_a: MOD:02020 ! N-timnodonoylated residue
 
 [Term]
 id: MOD:02020
@@ -36581,8 +36584,8 @@ property_value: DiffFormula "C 20 H 28 N 0 O 1" xsd:string
 property_value: DiffMono "284.214016" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00670
-is_a: MOD:02021
+is_a: MOD:00670 ! N-acylated residue
+is_a: MOD:02021 ! timnodonoylated residue
 
 [Term]
 id: MOD:02021
@@ -36594,8 +36597,8 @@ property_value: DiffFormula "C 20 H 28 N 0 O 1" xsd:string
 property_value: DiffMono "284.214016" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00649
-is_a: MOD:01155
+is_a: MOD:00649 ! acylated residue
+is_a: MOD:01155 ! lipoconjugated residue
 
 [Term]
 id: MOD:02022
@@ -36610,8 +36613,8 @@ property_value: MassAvg "438.71" xsd:float
 property_value: MassMono "438.324629" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:01875
-is_a: MOD:02023
+is_a: MOD:01875 ! N6-acylated L-lysine
+is_a: MOD:02023 ! N-cervonoylated residue
 
 [Term]
 id: MOD:02023
@@ -36623,8 +36626,8 @@ property_value: DiffFormula "C 22 H 30 N 0 O 1" xsd:string
 property_value: DiffMono "310.229666" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00670
-is_a: MOD:02024
+is_a: MOD:00670 ! N-acylated residue
+is_a: MOD:02024 ! cervonoylated residue
 
 [Term]
 id: MOD:02024
@@ -36636,8 +36639,8 @@ property_value: DiffFormula "C 22 H 30 N 0 O 1" xsd:string
 property_value: DiffMono "310.229666" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00649
-is_a: MOD:01155
+is_a: MOD:00649 ! acylated residue
+is_a: MOD:01155 ! lipoconjugated residue
 
 [Term]
 id: MOD:02025
@@ -36651,7 +36654,7 @@ property_value: MassAvg "257.24" xsd:float
 property_value: MassMono "257.101167" xsd:float
 property_value: Origin "E" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00906
+is_a: MOD:00906 ! modified L-glutamic acid residue
 
 [Term]
 id: MOD:02026
@@ -36666,9 +36669,9 @@ property_value: MassAvg "279.33" xsd:float
 property_value: MassMono "279.034748" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00905
-is_a: MOD:01862
-relationship: part_of MOD:00234
+is_a: MOD:00905 ! modified L-cysteine residue
+is_a: MOD:01862 ! disulfide conjugated residue
+relationship: part_of MOD:00234 ! L-cysteine glutathione disulfide
 
 [Term]
 id: MOD:02027
@@ -36677,10 +36680,10 @@ def: "A protein modification that effectively crosslinks the N6-amino of a pepti
 subset: PSI-MOD-slim
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:02047
-is_a: MOD:02051
-is_a: MOD:01875
-relationship: contains MOD:00134
+is_a: MOD:02047 ! crosslinked glycine residue
+is_a: MOD:02051 ! crosslinked L-lysine residue
+is_a: MOD:01875 ! N6-acylated L-lysine
+relationship: contains MOD:00134 ! N6-glycyl-L-lysine
 
 [Term]
 id: MOD:02028
@@ -36694,10 +36697,10 @@ property_value: DiffAvg "144.10" xsd:float
 property_value: DiffMono "144.102411" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:01426
-is_a: MOD:01705
-is_a: MOD:01709
-is_a: MOD:01513
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
+is_a: MOD:01705 ! isotope tagged reagent acylated residue
+is_a: MOD:01709 ! iTRAQ4plex reporter+balance reagent N-acylated residue
+is_a: MOD:01513 ! modifications with monoisotopic mass differences that are nominally equal at a resolution below 0.1 Da
 
 [Term]
 id: MOD:02029
@@ -36708,7 +36711,7 @@ property_value: DiffFormula "C 0 H 0 N 0 O 0" xsd:string
 property_value: DiffMono "0.000000" xsd:float
 property_value: Origin "X, P" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00915
+is_a: MOD:00915 ! modified L-proline residue
 
 [Term]
 id: MOD:02030
@@ -36719,7 +36722,7 @@ property_value: DiffFormula "C 0 H 0 N 0 O 0" xsd:string
 property_value: DiffMono "0.000000" xsd:float
 property_value: Origin "X, P" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00915
+is_a: MOD:00915 ! modified L-proline residue
 
 [Term]
 id: MOD:02031
@@ -36736,8 +36739,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:1519
 xref: GNO:G03382KH
-is_a: MOD:00725
-is_a: MOD:00160
+is_a: MOD:00725 ! complex glycosylation
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:02032
@@ -36754,8 +36757,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:1785
 xref: GNO:G70418MS
-is_a: MOD:00725
-is_a: MOD:00160
+is_a: MOD:00725 ! complex glycosylation
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:02033
@@ -36772,8 +36775,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:1484
 xref: GNO:G82119TF
-is_a: MOD:00725
-is_a: MOD:00160
+is_a: MOD:00725 ! complex glycosylation
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:02034
@@ -36790,8 +36793,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:1781
 xref: GNO:G50757KG
-is_a: MOD:00725
-is_a: MOD:00160
+is_a: MOD:00725 ! complex glycosylation
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:02035
@@ -36808,8 +36811,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:1509
 xref: GNO:G84820NF
-is_a: MOD:00725
-is_a: MOD:00160
+is_a: MOD:00725 ! complex glycosylation
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:02036
@@ -36826,8 +36829,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:1531
 xref: GNO:G70101JE
-is_a: MOD:00725
-is_a: MOD:00160
+is_a: MOD:00725 ! complex glycosylation
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:02037
@@ -36845,8 +36848,8 @@ property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:1480
 xref: GNO:G05724UK
-is_a: MOD:00725
-is_a: MOD:00160
+is_a: MOD:00725 ! complex glycosylation
+is_a: MOD:00160 ! N4-glycosyl-L-asparagine
 
 [Term]
 id: MOD:02038
@@ -36867,8 +36870,8 @@ property_value: Origin "H" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:34
 xref: uniprot.ptm:PTM-0176
-is_a: MOD:00599
-is_a: MOD:00661
+is_a: MOD:00599 ! monomethylated residue
+is_a: MOD:00661 ! methylated histidine
 
 [Term]
 id: MOD:02039
@@ -36876,7 +36879,7 @@ name: aminated residue
 def: "A protein modification that effectively replaces a hydrogen group with a amino group" []
 synonym: "AmRes" EXACT PSI-MOD-label []
 property_value: Origin "X" xsd:string
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:02040
@@ -36885,7 +36888,7 @@ def: "A protein modification that contains an L-alanine residue crosslinked to o
 subset: PSI-MOD-slim
 synonym: "XlnkAla" EXACT PSI-MOD-label []
 property_value: Origin "A" xsd:string
-is_a: MOD:00901
+is_a: MOD:00901 ! modified L-alanine residue
 
 [Term]
 id: MOD:02041
@@ -36894,7 +36897,7 @@ def: "A protein modification that contains an L-arginine residue crosslinked to
 subset: PSI-MOD-slim
 synonym: "XlnkArg" EXACT PSI-MOD-label []
 property_value: Origin "R" xsd:string
-is_a: MOD:00902
+is_a: MOD:00902 ! modified L-arginine residue
 
 [Term]
 id: MOD:02042
@@ -36903,7 +36906,7 @@ def: "A protein modification that contains an L-asparagine residue crosslinked t
 subset: PSI-MOD-slim
 synonym: "XlnkAsn" EXACT PSI-MOD-label []
 property_value: Origin "N" xsd:string
-is_a: MOD:00903
+is_a: MOD:00903 ! modified L-asparagine residue
 
 [Term]
 id: MOD:02043
@@ -36912,7 +36915,7 @@ def: "A protein modification that contains an L-aspartic acid residue crosslinke
 subset: PSI-MOD-slim
 synonym: "XlnkAsp" EXACT PSI-MOD-label []
 property_value: Origin "D" xsd:string
-is_a: MOD:00904
+is_a: MOD:00904 ! modified L-aspartic acid residue
 
 [Term]
 id: MOD:02044
@@ -36921,7 +36924,7 @@ def: "A protein modification that contains an L-cysteine residue crosslinked to
 subset: PSI-MOD-slim
 synonym: "XlnkCys" EXACT PSI-MOD-label []
 property_value: Origin "C" xsd:string
-is_a: MOD:00905
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:02045
@@ -36930,7 +36933,7 @@ def: "A protein modification that contains an L-glutamic acid residue crosslinke
 subset: PSI-MOD-slim
 synonym: "XlnkGlu" EXACT PSI-MOD-label []
 property_value: Origin "E" xsd:string
-is_a: MOD:00906
+is_a: MOD:00906 ! modified L-glutamic acid residue
 
 [Term]
 id: MOD:02046
@@ -36939,7 +36942,7 @@ def: "A protein modification that contains an L-glutamine residue crosslinked to
 subset: PSI-MOD-slim
 synonym: "XlnkGln" EXACT PSI-MOD-label []
 property_value: Origin "Q" xsd:string
-is_a: MOD:00907
+is_a: MOD:00907 ! modified L-glutamine residue
 
 [Term]
 id: MOD:02047
@@ -36948,7 +36951,7 @@ def: "A protein modification that contains a glycine residue crosslinked to one
 subset: PSI-MOD-slim
 synonym: "XlnkGly" EXACT PSI-MOD-label []
 property_value: Origin "G" xsd:string
-is_a: MOD:00908
+is_a: MOD:00908 ! modified glycine residue
 
 [Term]
 id: MOD:02048
@@ -36957,7 +36960,7 @@ def: "A protein modification that contains an L-histidine residue crosslinked to
 subset: PSI-MOD-slim
 synonym: "XlnkHis" EXACT PSI-MOD-label []
 property_value: Origin "H" xsd:string
-is_a: MOD:00909
+is_a: MOD:00909 ! modified L-histidine residue
 
 [Term]
 id: MOD:02049
@@ -36966,7 +36969,7 @@ def: "A protein modification that contains an L-isoleucine residue crosslinked t
 subset: PSI-MOD-slim
 synonym: "XlnkIle" EXACT PSI-MOD-label []
 property_value: Origin "I" xsd:string
-is_a: MOD:00910
+is_a: MOD:00910 ! modified L-isoleucine residue
 
 [Term]
 id: MOD:02050
@@ -36975,7 +36978,7 @@ def: "A protein modification that contains an L-leucine residue crosslinked to o
 subset: PSI-MOD-slim
 synonym: "XlnkLeu" EXACT PSI-MOD-label []
 property_value: Origin "L" xsd:string
-is_a: MOD:00911
+is_a: MOD:00911 ! modified L-leucine residue
 
 [Term]
 id: MOD:02051
@@ -36984,7 +36987,7 @@ def: "A protein modification that contains an L-lysine residue crosslinked to on
 subset: PSI-MOD-slim
 synonym: "XlnkLys" EXACT PSI-MOD-label []
 property_value: Origin "K" xsd:string
-is_a: MOD:00912
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:02052
@@ -36993,7 +36996,7 @@ def: "A protein modification that contains an L-methionine residue crosslinked t
 subset: PSI-MOD-slim
 synonym: "XlnkMet" EXACT PSI-MOD-label []
 property_value: Origin "M" xsd:string
-is_a: MOD:00913
+is_a: MOD:00913 ! modified L-methionine residue
 
 [Term]
 id: MOD:02053
@@ -37002,7 +37005,7 @@ def: "A protein modification that contains an L-phenylalanine residue crosslinke
 subset: PSI-MOD-slim
 synonym: "XlnkPhe" EXACT PSI-MOD-label []
 property_value: Origin "F" xsd:string
-is_a: MOD:00914
+is_a: MOD:00914 ! modified L-phenylalanine residue
 
 [Term]
 id: MOD:02054
@@ -37011,7 +37014,7 @@ def: "A protein modification that contains an L-proline residue crosslinked to o
 subset: PSI-MOD-slim
 synonym: "XlnkPro" EXACT PSI-MOD-label []
 property_value: Origin "P" xsd:string
-is_a: MOD:00915
+is_a: MOD:00915 ! modified L-proline residue
 
 [Term]
 id: MOD:02055
@@ -37020,7 +37023,7 @@ def: "A protein modification that contains an L-serine residue crosslinked to on
 subset: PSI-MOD-slim
 synonym: "XlnkSer" EXACT PSI-MOD-label []
 property_value: Origin "S" xsd:string
-is_a: MOD:00916
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:02056
@@ -37029,7 +37032,7 @@ def: "A protein modification that contains an L-threonine residue crosslinked to
 subset: PSI-MOD-slim
 synonym: "XlnkThr" EXACT PSI-MOD-label []
 property_value: Origin "T" xsd:string
-is_a: MOD:00917
+is_a: MOD:00917 ! modified L-threonine residue
 
 [Term]
 id: MOD:02057
@@ -37038,7 +37041,7 @@ def: "A protein modification that contains an L-tryptophan residue crosslinked t
 subset: PSI-MOD-slim
 synonym: "XlnkTrp" EXACT PSI-MOD-label []
 property_value: Origin "W" xsd:string
-is_a: MOD:00918
+is_a: MOD:00918 ! modified L-tryptophan residue
 
 [Term]
 id: MOD:02058
@@ -37047,7 +37050,7 @@ def: "A protein modification that contains an L-tyrosine residue crosslinked to
 subset: PSI-MOD-slim
 synonym: "XlnkTyr" EXACT PSI-MOD-label []
 property_value: Origin "Y" xsd:string
-is_a: MOD:00919
+is_a: MOD:00919 ! modified L-tyrosine residue
 
 [Term]
 id: MOD:02059
@@ -37056,7 +37059,7 @@ def: "A protein modification that contains an L-valine residue crosslinked to on
 subset: PSI-MOD-slim
 synonym: "XlnkVal" EXACT PSI-MOD-label []
 property_value: Origin "V" xsd:string
-is_a: MOD:00920
+is_a: MOD:00920 ! modified L-valine residue
 
 [Term]
 id: MOD:02060
@@ -37065,7 +37068,7 @@ def: "A protein modification that contains an D-asparagine residue crosslinked t
 subset: PSI-MOD-slim
 synonym: "XlnkDAsn" EXACT PSI-MOD-label []
 property_value: Origin "MOD:00203" xsd:string
-is_a: MOD:02097
+is_a: MOD:02097 ! modified D-asparagine residue
 
 [Term]
 id: MOD:02061
@@ -37073,7 +37076,7 @@ name: crosslinked L-selenocysteine residue
 def: "A protein modification that contains an L-selenocysteine residue crosslinked to one or more amino acid residues." [PubMed:18688235]
 subset: PSI-MOD-slim
 property_value: Origin "U" xsd:string
-is_a: MOD:01158
+is_a: MOD:01158 ! modified L-selenocysteine residue
 
 [Term]
 id: MOD:02062
@@ -37081,7 +37084,7 @@ name: crosslinked N-formyl-L-methionine residue
 def: "A protein modification that contains an N-formyl-L-methionine residue crosslinked to one or more amino acid residues." [PubMed:18688235]
 subset: PSI-MOD-slim
 property_value: Origin "MOD:00030" xsd:string
-is_a: MOD:01450
+is_a: MOD:01450 ! modified N-formyl-L-methionine residue
 
 [Term]
 id: MOD:02063
@@ -37090,7 +37093,7 @@ def: "A protein modification that contains an D-phenylalanine residue crosslinke
 subset: PSI-MOD-slim
 synonym: "XlnkDPhe" EXACT PSI-MOD-label []
 property_value: Origin "F" xsd:string
-is_a: MOD:00201
+is_a: MOD:00201 ! D-phenylalanine
 
 [Term]
 id: MOD:02064
@@ -37099,7 +37102,7 @@ def: "A protein modification that contains an D-serine residue crosslinked to on
 subset: PSI-MOD-slim
 synonym: "XlnkDSer" EXACT PSI-MOD-label []
 property_value: Origin "S" xsd:string
-is_a: MOD:00202
+is_a: MOD:00202 ! D-serine (Ser)
 
 [Term]
 id: MOD:02065
@@ -37107,7 +37110,7 @@ name: metal or metal cluster coordinated L-alanine residue
 def: "A protein modification that contains an L-alanine residue coordinated to one or more metal atoms or metal clusters." [PubMed:18688235]
 subset: PSI-MOD-slim
 property_value: Origin "A" xsd:string
-is_a: MOD:00901
+is_a: MOD:00901 ! modified L-alanine residue
 
 [Term]
 id: MOD:02066
@@ -37115,7 +37118,7 @@ name: metal or metal cluster coordinated L-aspartic acid residue
 def: "A protein modification that contains an L-aspartic acid residue coordinated to one or more metal atoms or metal clusters." [PubMed:18688235]
 subset: PSI-MOD-slim
 property_value: Origin "D" xsd:string
-is_a: MOD:00904
+is_a: MOD:00904 ! modified L-aspartic acid residue
 
 [Term]
 id: MOD:02067
@@ -37123,7 +37126,7 @@ name: metal or metal cluster coordinated L-cysteine residue
 def: "A protein modification that contains an L-cysteine residue coordinated to one or more metal atoms or metal clusters." [PubMed:18688235]
 subset: PSI-MOD-slim
 property_value: Origin "C" xsd:string
-is_a: MOD:00905
+is_a: MOD:00905 ! modified L-cysteine residue
 
 [Term]
 id: MOD:02068
@@ -37131,7 +37134,7 @@ name: metal or metal cluster coordinated L-glutamic acid residue
 def: "A protein modification that contains an L-glutamic acid residue coordinated to one or more metal atoms or metal clusters." [PubMed:18688235]
 subset: PSI-MOD-slim
 property_value: Origin "E" xsd:string
-is_a: MOD:00906
+is_a: MOD:00906 ! modified L-glutamic acid residue
 
 [Term]
 id: MOD:02069
@@ -37139,7 +37142,7 @@ name: metal or metal cluster coordinated L-glutamine residue
 def: "A protein modification that contains an L-glutamine residue coordinated to one or more metal atoms or metal clusters." [PubMed:18688235]
 subset: PSI-MOD-slim
 property_value: Origin "Q" xsd:string
-is_a: MOD:00907
+is_a: MOD:00907 ! modified L-glutamine residue
 
 [Term]
 id: MOD:02070
@@ -37147,7 +37150,7 @@ name: metal or metal cluster coordinated L-histidine residue
 def: "A protein modification that contains an L-histidine residue coordinated to one or more metal atoms or metal clusters." [PubMed:18688235]
 subset: PSI-MOD-slim
 property_value: Origin "H" xsd:string
-is_a: MOD:00909
+is_a: MOD:00909 ! modified L-histidine residue
 
 [Term]
 id: MOD:02071
@@ -37155,7 +37158,7 @@ name: metal or metal cluster coordinated L-methionine residue
 def: "A protein modification that contains an L-methionine residue coordinated to one or more metal atoms or metal clusters." [PubMed:18688235]
 subset: PSI-MOD-slim
 property_value: Origin "M" xsd:string
-is_a: MOD:00913
+is_a: MOD:00913 ! modified L-methionine residue
 
 [Term]
 id: MOD:02072
@@ -37163,7 +37166,7 @@ name: metal or metal cluster coordinated L-serine residue
 def: "A protein modification that contains an L-serine residue coordinated to one or more metal atoms or metal clusters." [PubMed:18688235]
 subset: PSI-MOD-slim
 property_value: Origin "S" xsd:string
-is_a: MOD:00916
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:02073
@@ -37171,7 +37174,7 @@ name: metal or metal cluster coordinated L-selenocysteine residue
 def: "A protein modification that contains an L-selenocysteine residue coordinated to one or more metal atoms or metal clusters." [PubMed:18688235]
 subset: PSI-MOD-slim
 property_value: Origin "U" xsd:string
-is_a: MOD:01158
+is_a: MOD:01158 ! modified L-selenocysteine residue
 
 [Term]
 id: MOD:02074
@@ -37179,7 +37182,7 @@ name: metal or metal cluster coordinated L-lysine residue
 def: "A protein modification that contains an L-lysine residue coordinated to one or more metal atoms or metal clusters." [PubMed:18688235]
 subset: PSI-MOD-slim
 property_value: Origin "K" xsd:string
-is_a: MOD:00912
+is_a: MOD:00912 ! modified L-lysine residue
 
 [Term]
 id: MOD:02075
@@ -37187,7 +37190,7 @@ name: metal or metal cluster coordinated L-tyrosine residue
 def: "A protein modification that contains an L-tyrosine residue coordinated to one or more metal atoms or metal clusters." [PubMed:18688235]
 subset: PSI-MOD-slim
 property_value: Origin "Y" xsd:string
-is_a: MOD:00919
+is_a: MOD:00919 ! modified L-tyrosine residue
 
 [Term]
 id: MOD:02076
@@ -37195,7 +37198,7 @@ name: metal or metal cluster coordinated L-arginine residue
 def: "A protein modification that contains an L-arginine residue coordinated to one or more metal atoms or metal clusters." [PubMed:18688235]
 subset: PSI-MOD-slim
 property_value: Origin "R" xsd:string
-is_a: MOD:00902
+is_a: MOD:00902 ! modified L-arginine residue
 
 [Term]
 id: MOD:02077
@@ -37209,7 +37212,7 @@ property_value: DiffMono "28.990164" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:275
-is_a: MOD:01156
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:02078
@@ -37220,7 +37223,7 @@ synonym: "Acetyl" RELATED PSI-MS-label []
 synonym: "AcRes" EXACT PSI-MOD-label []
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:00649
+is_a: MOD:00649 ! acylated residue
 
 [Term]
 id: MOD:02079
@@ -37235,7 +37238,7 @@ property_value: DiffFormula "C 4 H 4 N 0 O 2" xsd:string
 property_value: DiffMono "84.021129" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "artifact" xsd:string
-is_a: MOD:02078
+is_a: MOD:02078 ! acetylated residue
 
 [Term]
 id: MOD:02080
@@ -37251,8 +37254,8 @@ property_value: MassAvg "172.16" xsd:float
 property_value: MassMono "172.060983" xsd:float
 property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:02079
-is_a: MOD:00916
+is_a: MOD:02079 ! diacetylated residue
+is_a: MOD:00916 ! modified L-serine residue
 
 [Term]
 id: MOD:02081
@@ -37266,9 +37269,9 @@ property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
 property_value: TermSpec "N-term" xsd:string
 xref: Unimod:64
-is_a: MOD:01029
-is_a: MOD:01696
-is_a: MOD:01426
+is_a: MOD:01029 ! succinylated residue
+is_a: MOD:01696 ! alpha-amino acylated residue
+is_a: MOD:01426 ! isotope tagged reagent derivatized residue
 
 [Term]
 id: MOD:02082
@@ -37280,7 +37283,7 @@ property_value: DiffAvg "-20.03" xsd:float
 property_value: DiffFormula "C 0 H -4 N 0 O -1" xsd:string
 property_value: DiffMono "-20.026215" xsd:float
 property_value: Origin "X" xsd:string
-is_a: MOD:00683
+is_a: MOD:00683 ! dehydrogenated residue
 
 [Term]
 id: MOD:02083
@@ -37293,7 +37296,7 @@ property_value: DiffAvg "456.35" xsd:float
 property_value: DiffMono "456.104615" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00896
+is_a: MOD:00896 ! FMN modified residue
 
 [Term]
 id: MOD:02084
@@ -37306,7 +37309,7 @@ property_value: DiffFormula "C 17 H 19 N 4 O 9 P 1" xsd:string
 property_value: DiffMono "454.088965" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00896
+is_a: MOD:00896 ! FMN modified residue
 
 [Term]
 id: MOD:02085
@@ -37319,7 +37322,7 @@ property_value: DiffFormula "C 17 H 19 N 4 O 9 P 1" xsd:string
 property_value: DiffMono "454.088965" xsd:float
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00896
+is_a: MOD:00896 ! FMN modified residue
 
 [Term]
 id: MOD:02086
@@ -37327,8 +37330,8 @@ name: brominated phenylalanine
 def: "A protein modification that effectively substitutes a hydrogen atom of an L-phenylalanine residue with a bromine atom." [PubMed:18688235]
 synonym: "BrPhe" EXACT PSI-MOD-label []
 property_value: Origin "F" xsd:string
-is_a: MOD:00754
-is_a: MOD:01066
+is_a: MOD:00754 ! brominated residue
+is_a: MOD:01066 ! halogenated phenylalanine
 
 [Term]
 id: MOD:02087
@@ -37338,7 +37341,7 @@ subset: PSI-MOD-slim
 synonym: "ADPRibRes" EXACT PSI-MOD-label []
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00701
+is_a: MOD:00701 ! nucleotide or nucleic acid modified residue
 
 [Term]
 id: MOD:02088
@@ -37348,8 +37351,8 @@ comment: This represents the replacement of an encoded residue in a polypeptide,
 subset: PSI-MOD-slim
 property_value: Origin "X" xsd:string
 property_value: Source "natural" xsd:string
-is_a: MOD:00009
-is_a: MOD:01156
+is_a: MOD:00009 ! natural residue
+is_a: MOD:01156 ! protein modification categorized by chemical process
 
 [Term]
 id: MOD:02089
@@ -37369,8 +37372,8 @@ property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:417
 xref: uniprot.ptm:PTM-0501
-is_a: MOD:00916
-is_a: MOD:01166
+is_a: MOD:00916 ! modified L-serine residue
+is_a: MOD:01166 ! uridylated residue
 
 [Term]
 id: MOD:02090
@@ -37390,8 +37393,8 @@ property_value: Origin "T" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:417
 xref: uniprot.ptm:PTM-0502
-is_a: MOD:00917
-is_a: MOD:01166
+is_a: MOD:00917 ! modified L-threonine residue
+is_a: MOD:01166 ! uridylated residue
 
 [Term]
 id: MOD:02091
@@ -37410,8 +37413,8 @@ property_value: Origin "S" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:405
 xref: uniprot.ptm:PTM-0651
-is_a: MOD:00916
-is_a: MOD:01165
+is_a: MOD:00916 ! modified L-serine residue
+is_a: MOD:01165 ! adenylated residue
 
 [Term]
 id: MOD:02092
@@ -37428,8 +37431,8 @@ property_value: MassMono "233.035793" xsd:float
 property_value: Origin "C" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0676
-is_a: MOD:00905
-is_a: MOD:00001
+is_a: MOD:00905 ! modified L-cysteine residue
+is_a: MOD:00001 ! alkylated residue
 
 [Term]
 id: MOD:02093
@@ -37446,7 +37449,7 @@ property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: Unimod:1849
 xref: uniprot.ptm:PTM-0638
-is_a: MOD:01875
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:02094
@@ -37462,7 +37465,7 @@ property_value: MassMono "214.131742" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0499
-is_a: MOD:01875
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:02095
@@ -37478,7 +37481,7 @@ property_value: MassMono "242.126657" xsd:float
 property_value: Origin "K" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0487
-is_a: MOD:01875
+is_a: MOD:01875 ! N6-acylated L-lysine
 
 [Term]
 id: MOD:02096
@@ -37496,11 +37499,11 @@ property_value: MassMono "128.058578" xsd:float
 property_value: Origin "N" xsd:string
 property_value: Source "natural" xsd:string
 xref: uniprot.ptm:PTM-0691
-is_a: MOD:00599
-is_a: MOD:00602
-is_a: MOD:00673
-is_a: MOD:02097
-is_a: MOD:00894
+is_a: MOD:00599 ! monomethylated residue
+is_a: MOD:00602 ! N-methylated residue
+is_a: MOD:00673 ! methylated asparagine
+is_a: MOD:02097 ! modified D-asparagine residue
+is_a: MOD:00894 ! residues isobaric at 128.058578 Da
 
 [Term]
 id: MOD:02097
@@ -37508,7 +37511,307 @@ name: modified D-asparagine residue
 def: "A protein modification that modifies a D-asparagine residue." [PubMed:18688235]
 subset: PSI-MOD-slim
 synonym: "ModDAsn" EXACT PSI-MOD-label []
-is_a: MOD:00203
+is_a: MOD:00203 ! D-asparagine
+
+[Term]
+id: MOD:02106
+name: 4-hydroxy-L-tryptophan
+def: "A protein modification that effectively converts an L-tryptophan residue to a 4-hydroxy-L-tryptophan." [PMID:32911085]
+synonym: "(S)-2-Amino-3-(4-hydroxy-1H-indol-3-yl)propanoic acid" EXACT PSI-MOD-alternate []
+property_value: DiffAvg "16.00" xsd:float
+property_value: DiffFormula "C 0 H 0 N 0 O 1" xsd:string
+property_value: DiffMono "15.994915" xsd:float
+property_value: Formula "C 11 H 10 N 2 O 2" xsd:string
+property_value: MassAvg "202.21" xsd:float
+property_value: MassMono "202.074228" xsd:float
+property_value: Origin "W" xsd:string
+property_value: Source "hypothetical" xsd:string
+is_a: MOD:01622 ! monohydroxylated tryptophan
+
+[Term]
+id: MOD:02107
+name: 5-hydroxy-L-tryptophan
+def: "A protein modification that effectively converts an L-tryptophan residue to a 5-hydroxy-L-tryptophan." [PMID:32911085]
+synonym: "(S)-2-Amino-3-(5-hydroxy-1H-indol-3-yl)propanoic acid" EXACT PSI-MOD-alternate []
+property_value: DiffAvg "16.00" xsd:float
+property_value: DiffFormula "C 0 H 0 N 0 O 1" xsd:string
+property_value: DiffMono "15.994915" xsd:float
+property_value: Formula "C 11 H 10 N 2 O 2" xsd:string
+property_value: MassAvg "202.21" xsd:float
+property_value: MassMono "202.074228" xsd:float
+property_value: Origin "W" xsd:string
+property_value: Source "hypothetical" xsd:string
+is_a: MOD:01622 ! monohydroxylated tryptophan
+
+[Term]
+id: MOD:02108
+name: 6-hydroxy-L-tryptophan
+def: "A protein modification that effectively converts an L-tryptophan residue to a 6-hydroxy-L-tryptophan." [PMID:32911085]
+synonym: "(S)-2-Amino-3-(4-hydroxy-1H-indol-3-yl)propanoic acid" EXACT PSI-MOD-alternate []
+property_value: DiffAvg "16.00" xsd:float
+property_value: DiffFormula "C 0 H 0 N 0 O 1" xsd:string
+property_value: DiffMono "15.994915" xsd:float
+property_value: Formula "C 11 H 10 N 2 O 2" xsd:string
+property_value: MassAvg "202.21" xsd:float
+property_value: MassMono "202.074228" xsd:float
+property_value: Origin "W" xsd:string
+property_value: Source "hypothetical" xsd:string
+is_a: MOD:01622 ! monohydroxylated tryptophan
+
+[Term]
+id: MOD:02109
+name: oxindolylalanine
+def: "A protein modification that effectively converts an L-tryptophan residue to a oxindolylalanine." [PMID:32911085]
+synonym: "Oxindolyl-L-alanine" EXACT PSI-MOD-alternate []
+synonym: "2-amino-3-(2-oxoindolin-3-yl)propanoic acid" EXACT PSI-MOD-alternate []
+property_value: DiffAvg "16.00" xsd:float
+property_value: DiffFormula "C 0 H 0 N 0 O 1" xsd:string
+property_value: DiffMono "15.994915" xsd:float
+property_value: Formula "C 11 H 10 N 2 O 2" xsd:string
+property_value: MassAvg "202.21" xsd:float
+property_value: MassMono "202.074228" xsd:float
+property_value: Origin "W" xsd:string
+property_value: Source "hypothetical" xsd:string
+is_a: MOD:01622 ! monohydroxylated tryptophan
+
+[Term]
+id: MOD:02110
+name: 5-hydroxy-L-proline
+def: "A protein modification that effectively converts an L-proline residue to 5-hydroxy-L-proline" [ChEBI:18095, PubMed:11292863, PubMed:2400108, PubMed:3734192, RESID:AA0030]
+subset: PSI-MOD-slim
+synonym: "(2S,5S)-5-hydroxypyrrolidine-2-carboxylic acid" EXACT PSI-MOD-alternate []
+property_value: DiffAvg "16.00" xsd:float
+property_value: DiffFormula "C 0 H 0 N 0 O 1" xsd:string
+property_value: DiffMono "15.994915" xsd:float
+property_value: Formula "C 5 H 7 N 1 O 2" xsd:string
+property_value: MassAvg "113.12" xsd:float
+property_value: MassMono "113.047678" xsd:float
+property_value: Origin "P" xsd:string
+property_value: Source "natural" xsd:string
+is_a: MOD:01024 ! monohydroxylated proline
+
+[Term]
+id: MOD:02111
+name: (2S,4S)-5-hydroxyleucine
+def: "A protein modification that effectively converts an L-leucine residue to a (2S,4S)-5-hydroxyleucine." [PubMed:9164839]
+synonym: "(2S,4S)-2-amino-5-hydroxy-4-methylpentanoic acid" EXACT PSI-MOD-alternate []
+property_value: DiffAvg "16.00" xsd:float
+property_value: DiffFormula "C 0 H 0 N 0 O 1" xsd:string
+property_value: DiffMono "15.994915" xsd:float
+property_value: Formula "C 6 H 11 N 1 O 2" xsd:string
+property_value: MassAvg "129.16" xsd:float
+property_value: MassMono "129.078979" xsd:float
+property_value: Origin "L" xsd:string
+property_value: Source "artifact" xsd:string
+is_a: MOD:01411 ! monohydroxylated leucine
+
+[Term]
+id: MOD:02112
+name: 4,5-Dihydroxytryptophan
+def: "A protein modification that converts an L-tryptophan residue to 4,5-Dihydroxytryptophan." [PubMed:16046449, PubMed:30267362]
+subset: PSI-MOD-slim
+synonym: "dihydroxy" RELATED Unimod-description []
+synonym: "Dioxidation" RELATED PSI-MS-label []
+synonym: "Double oxidation of Trp" EXACT DeltaMass-label []
+synonym: "(2S)-2-amino-3-(4,5-dihydroxy-1H-indol-3-yl)propanoic acid" EXACT PSI-MOD-alternate []
+property_value: DiffAvg "32.00" xsd:float
+property_value: DiffFormula "O 2" xsd:string
+property_value: DiffMono "31.989829" xsd:float
+property_value: Formula "C 11 H 10 N 2 O 3" xsd:string
+property_value: MassAvg "218.21" xsd:float
+property_value: MassMono "218.069142" xsd:float
+property_value: Origin "W" xsd:string
+property_value: Source "hypothetical" xsd:string
+xref: Unimod:425
+is_a: MOD:00918 ! modified L-tryptophan residue
+
+[Term]
+id: MOD:02113
+name: 5,6-Dihydroxytryptophan
+def: "A protein modification that converts an L-tryptophan residue to 5,6-Dihydroxytryptophan." [PubMed:16046449, PubMed:30267362]
+subset: PSI-MOD-slim
+synonym: "dihydroxy" RELATED Unimod-description []
+synonym: "Dioxidation" RELATED PSI-MS-label []
+synonym: "Double oxidation of Trp" EXACT DeltaMass-label []
+synonym: "(2S)-2-amino-3-(5,6-dihydroxy-1H-indol-3-yl)propanoic acid" EXACT PSI-MOD-alternate []
+property_value: DiffAvg "32.00" xsd:float
+property_value: DiffFormula "O 2" xsd:string
+property_value: DiffMono "31.989829" xsd:float
+property_value: Formula "C 11 H 10 N 2 O 3" xsd:string
+property_value: MassAvg "218.21" xsd:float
+property_value: MassMono "218.069142" xsd:float
+property_value: Origin "W" xsd:string
+property_value: Source "hypothetical" xsd:string
+xref: Unimod:425
+is_a: MOD:00918 ! modified L-tryptophan residue
+
+[Term]
+id: MOD:02114
+name: 5,7-Dihydroxytryptophan
+def: "A protein modification that converts an L-tryptophan residue to 5,7-Dihydroxytryptophan." [PubMed:16046449, PubMed:30267362]
+subset: PSI-MOD-slim
+synonym: "dihydroxy" RELATED Unimod-description []
+synonym: "Dioxidation" RELATED PSI-MS-label []
+synonym: "Double oxidation of Trp" EXACT DeltaMass-label []
+synonym: "(2S)-2-amino-3-(5,7-dihydroxy-1H-indol-3-yl)propanoic acid" EXACT PSI-MOD-alternate []
+property_value: DiffAvg "32.00" xsd:float
+property_value: DiffFormula "O 2" xsd:string
+property_value: DiffMono "31.989829" xsd:float
+property_value: Formula "C 11 H 10 N 2 O 3" xsd:string
+property_value: MassAvg "218.21" xsd:float
+property_value: MassMono "218.069142" xsd:float
+property_value: Origin "W" xsd:string
+property_value: Source "hypothetical" xsd:string
+xref: Unimod:425
+is_a: MOD:00918 ! modified L-tryptophan residue
+
+[Term]
+id: MOD:02115
+name: Dioxindolylalanine
+def: "A protein modification that converts an L-tryptophan residue to dioxindolylalanine." [PubMed:10554268, PubMed:32911085]
+subset: PSI-MOD-slim
+synonym: "dihydroxy" RELATED Unimod-description []
+synonym: "Dioxidation" RELATED PSI-MS-label []
+synonym: "Double oxidation of Trp" EXACT DeltaMass-label []
+synonym: "(alphaS)-alpha-Amino-2,3-dihydro-3-hydroxy-2-oxo-1H-indole-3-propanoic acid" EXACT PSI-MOD-alternate []
+synonym: "(2S)-2-amino-3-(3-hydroxy-2-oxo-1H-indol-3-yl)propanoic acid" EXACT PSI-MOD-alternate []
+synonym: "Dioxindolyl-L-alanine" EXACT PSI-MOD-alternate []
+property_value: DiffAvg "32.00" xsd:float
+property_value: DiffFormula "O 2" xsd:string
+property_value: DiffMono "31.989829" xsd:float
+property_value: Formula "C 11 H 10 N 2 O 3" xsd:string
+property_value: MassAvg "218.21" xsd:float
+property_value: MassMono "218.069142" xsd:float
+property_value: Origin "W" xsd:string
+property_value: Source "artifact" xsd:string
+xref: Unimod:425
+is_a: MOD:00918 ! modified L-tryptophan residue
+
+[Term]
+id: MOD:02098
+name: residue modified by radical mechanism
+def: "A chemical transformation driven by a radical reaction." [PubMed:14670063, doi:https\://pubs.acs.org/doi/10.1021/ac035104h]
+
+[Term]
+id: MOD:02099
+name: residue modified by radical hydroxylation
+def: "A hydroxyl substition induced by a radical reaction." [PubMed:17683160]
+is_a: MOD:02098 ! residue modified by radical mechanism
+
+[Term]
+id: MOD:02100
+name: N2-Formyl-L-asparagine
+def: "A protein modification that effectively transforms an L-histidine residue to N2-formyl asparagine" [osti.article:6518101, doi:10.1016/0040-4039(91)80099-R]
+synonym: "Nω-formyl asparagine" EXACT PSI-MOD-label []
+synonym: "(2S)-4-amino-2-formamido-4-oxobutanoic acid" EXACT PSI-MOD-label []
+synonym: "Formylasparagine" EXACT PSI-MOD-label []
+subset: PSI-MOD-slim
+property_value: DiffAvg "4.97" xsd:float
+property_value: DiffFormula "H -1 C -1 N -1 O 2" xsd:string
+property_value: DiffMono "4.978930" xsd:float
+property_value: Formula "C 5 H 6 N 2 O 3" xsd:string
+property_value: MassAvg "142.04" xsd:float
+property_value: MassMono "142.03784" xsd:float
+property_value: Origin "H" xsd:string
+property_value: Source "artifact" xsd:string
+xref: Unimod:1917
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:02099 ! residue modified by radical hydroxylation
+
+[Term]
+id: MOD:02101
+name: 2-Amino-4,5-dioxopentanoic acid
+def: "A protein modification that effectively transforms a histidine side chain to that of 2-Amino-4,5-dioxopentanoic acid" [PubMed:14670063]
+subset: PSI-MOD-slim
+property_value: DiffAvg "-10.04" xsd:float
+property_value: DiffFormula "H -2 C -1 N -2 O 2" xsd:string
+property_value: DiffMono "-10.031969" xsd:float
+property_value: Formula "C 5 H 5 N 1 O 3" xsd:string
+property_value: MassAvg "127.03" xsd:float
+property_value: MassMono "127.026941" xsd:float
+property_value: Origin "H" xsd:string
+property_value: Source "artifact" xsd:string
+is_a: MOD:00909 ! modified L-histidine residue
+is_a: MOD:02099 ! residue modified by radical hydroxylation
+
+[Term]
+id: MOD:02102
+name: 2-hydroxy-L-phenylalanine
+def: "A protein modification that effectively converts a L-Phenylalanine residue to 2-hydroxy-L-phenylalanine." [PubMed:8509373]
+synonym: "DL-o-Tyrosine" EXACT PSI-MOD-label []
+synonym: "2-amino-3-(2-hydroxyphenyl)propanoic acid" EXACT PSI-MOD-label []
+synonym: "O-Tyrosine" EXACT PSI-MOD-label []
+synonym: "o-tyrosine" EXACT PSI-MOD-alternate []
+subset: PSI-MOD-slim
+property_value: DiffAvg "16.0" xsd:float
+property_value: DiffFormula "O 1" xsd:string
+property_value: DiffMono "15.994915" xsd:float
+property_value: Formula "C 9 H 9 N 1 O 2" xsd:string
+property_value: MassAvg "163.06" xsd:float
+property_value: MassMono "163.063325" xsd:float
+property_value: Origin "F" xsd:string
+property_value: Source "artifact" xsd:string
+xref: Unimod:35
+is_a: MOD:02116 ! monohydroxylated phenylalanine
+is_a: MOD:02099 ! residue modified by radical hydroxylation
+
+[Term]
+id: MOD:02104
+name: 4-hydroxy-L-phenylalanine
+def: "A protein modification that effectively substitutes a hydroxy group at position 4 of L-phenylalanine" [PubMed:7408053]
+synonym: "L-tyrosine" EXACT PSI-MOD-alternate []
+synonym: "L-Tyrosine" EXACT PSI-MOD-alternate []
+synonym: "(2S)-2-amino-3-(4-hydroxyphenyl)propanoic acid" EXACT PSI-MOD-alternate []
+synonym: "Phe->Tyr" EXACT PSI-MOD-alternate []
+subset: PSI-MOD-slim
+property_value: DiffFormula "O 1" xsd:string
+property_value: Origin "F" xsd:string
+xref: Unimod:35
+property_value: DiffAvg "16.00" xsd:float
+property_value: DiffMono "15.994915" xsd:float
+property_value: Formula "C 9 H 9 N 1 O 2" xsd:string
+property_value: MassAvg "163.18" xsd:float
+property_value: MassMono "163.063329" xsd:float
+property_value: Source "artifact" xsd:string
+is_a: MOD:00914 ! modified L-phenylalanine residue
+is_a: MOD:02116 ! monohydroxylated phenylalanine
+
+[Term]
+id: MOD:02105
+name: L-2,5-dihydroxyphenylalanine (Phe)
+def: "A protein modification that effectively converts an L-tyrosine residue to L-2',5'-dihydroxyphenylalanine." [doi:10.1016/j.radphyschem.2003.11.008]
+subset: PSI-MOD-slim
+synonym: "2-amino-3-(2,5-dihydroxyphenyl)propanoic acid" EXACT PSI-MOD-label []
+synonym: "2,5-Dihydroxyphenylalanine" EXACT PSI-MOD-label []
+synonym: "2,5-Dioxyphenylalanine" EXACT PSI-MOD-label []
+property_value: DiffAvg "32.00" xsd:float
+property_value: DiffFormula "C 0 H 0 N 0 O 1" xsd:string
+property_value: DiffMono "31.989828" xsd:float
+property_value: Formula "C 9 H 9 N 1 O 3" xsd:string
+property_value: MassAvg "179.18" xsd:float
+property_value: MassMono "179.058243" xsd:float
+property_value: Origin "F" xsd:string
+property_value: Source "artifact" xsd:string
+is_a: MOD:00428 ! dihydroxylated residue
+is_a: MOD:00914 ! modified L-phenylalanine residue
+
+[Term]
+id: MOD:02116
+name: monohydroxylated phenylalanine
+def: "A protein modification that effectively converts an L-phenylalanine residue to a monohydroxylated phenylalanine." [Unimod:35#F]
+subset: PSI-MOD-slim
+synonym: "Oxidation" RELATED PSI-MS-label []
+property_value: DiffAvg "16.00" xsd:float
+property_value: DiffFormula "C 0 H 0 N 0 O 1" xsd:string
+property_value: DiffMono "15.994915" xsd:float
+property_value: Formula "C 6 H 12 N 2 O 2" xsd:string
+property_value: MassAvg "144.17" xsd:float
+property_value: MassMono "144.089878" xsd:float
+property_value: Origin "F" xsd:string
+property_value: Source "artifact" xsd:string
+xref: Unimod:35
+is_a: MOD:00425 ! monohydroxylated residue
+is_a: MOD:00914 ! modified L-phenylalanine residue
 
 [Typedef]
 id: contains
diff --git a/PSI-MOD.owl b/PSI-MOD.owl
index cdc12a0..973ac05 100644
--- a/PSI-MOD.owl
+++ b/PSI-MOD.owl
@@ -10,11 +10,11 @@
      xmlns:rdfs="http://www.w3.org/2000/01/rdf-schema#"
      xmlns:oboInOwl="http://www.geneontology.org/formats/oboInOwl#">
     <owl:Ontology rdf:about="http://purl.obolibrary.org/obo/mod.owl">
-        <owl:versionIRI rdf:resource="http://purl.obolibrary.org/obo/mod/1.031.6/mod.owl"/>
-        <oboInOwl:date rdf:datatype="http://www.w3.org/2001/XMLSchema#string">13:06:2021 12:12</oboInOwl:date>
+        <owl:versionIRI rdf:resource="http://purl.obolibrary.org/obo/mod/1.032.4/mod.owl"/>
+        <oboInOwl:date rdf:datatype="http://www.w3.org/2001/XMLSchema#string">17:11:2025 12:12</oboInOwl:date>
         <oboInOwl:default-namespace rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PSI-MOD</oboInOwl:default-namespace>
         <oboInOwl:hasOBOFormatVersion rdf:datatype="http://www.w3.org/2001/XMLSchema#string">1.2</oboInOwl:hasOBOFormatVersion>
-        <oboInOwl:saved-by rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Joshua Klein</oboInOwl:saved-by>
+        <oboInOwl:saved-by rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Eric Deutsch</oboInOwl:saved-by>
         <rdfs:comment rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Annotation note 01 - &quot;[PSI-MOD:ref]&quot; has been replaced by PubMed:18688235.</rdfs:comment>
         <rdfs:comment rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Annotation note 02 - When an entry in the RESID Database is annotated with different sources because the same modification can arise from different encoded amino acids, then the PSI-MOD definition for each different source instance carries the RESID cross-reference followed by a hash symbol &quot;#&quot; and a 3 or 4 character label. When an entry in the RESID Database is annotated as a general modification with the same enzymatic activity producing different chemical structures depending on natural variation in the nonproteinaceous substrate, on secondary modifications that do not change the nature of the primary modification, or on a combination of a primary and one or more secondary modifications on the same residue, then the PSI-MOD definition for each different instance carries the RESID cross-reference followed by the special tag &quot;#var&quot;.</rdfs:comment>
         <rdfs:comment rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Annotation note 03 - When an entry in the Unimod database is annotated as a general modification, and one or more instance sites are listed, then the PSI-MOD definition for each different site instance carries the Unimod cross-reference followed by a hash symbol and an amino acid code, &quot;N-term&quot; or &quot;C-term&quot;.</rdfs:comment>
@@ -26,7 +26,7 @@
         <rdfs:comment rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Annotation note 09 - The Open Mass Spectrometry Search Algorithm, OMSSA, enumerated list of modifications are being incorporated. The string values are synonyms with the synonymtypedef &quot;OMSSA-label&quot;, and their integer values (which are supposed to be stable) are definition cross-references.</rdfs:comment>
         <rdfs:comment rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Annotation note 10 - GNOme is the Glycan Naming and Subsumption Ontology (https://gnome.glyomics.org/), an ontology for the support of glycomics.  PSI-MOD does not have all possible glycans in its entries, just the ones that are noted to be on proteins and have been requested for addition.  GNOme uses GlyTouCan (http://glytoucan.org/) to provide stable accessions for glycans described at varyious degrees of characterization, including compositions (no linkage) and topologies (no carbon bond positions or anomeric configurations).</rdfs:comment>
         <rdfs:comment rdf:datatype="http://www.w3.org/2001/XMLSchema#string">ISO-8601 date: 2022-06-13 12:12Z</rdfs:comment>
-        <rdfs:comment rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PSI-MOD version: 1.031.6</rdfs:comment>
+        <rdfs:comment rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PSI-MOD version: 1.032.4</rdfs:comment>
         <rdfs:comment rdf:datatype="http://www.w3.org/2001/XMLSchema#string">RESID release: 75.00</rdfs:comment>
     </owl:Ontology>
     
@@ -21409,7 +21409,6 @@
         <oboInOwl:hasRelatedSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">glutathione disulfide</oboInOwl:hasRelatedSynonym>
         <oboInOwl:id rdf:datatype="http://www.w3.org/2001/XMLSchema#string">MOD:00234</oboInOwl:id>
         <oboInOwl:inSubset rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-slim"/>
-        <rdfs:comment rdf:datatype="http://www.w3.org/2001/XMLSchema#string">From DeltaMass: Average Mass: 305</rdfs:comment>
         <rdfs:comment rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Glutamyl-transpeptidase cleaves glutathione into cysteinylglycine (Cys-Gly) and a Glu residue. [PubMed: 28537416]</rdfs:comment>
         <rdfs:label rdf:datatype="http://www.w3.org/2001/XMLSchema#string">L-cysteine glutathione disulfide</rdfs:label>
     </owl:Class>
@@ -76010,6 +76009,7 @@
     <owl:Class rdf:about="http://purl.obolibrary.org/obo/MOD_01385">
         <rdfs:subClassOf rdf:resource="http://purl.obolibrary.org/obo/MOD_00677"/>
         <rdfs:subClassOf rdf:resource="http://purl.obolibrary.org/obo/MOD_00914"/>
+        <rdfs:subClassOf rdf:resource="http://purl.obolibrary.org/obo/MOD_02116"/>
         <obo:IAO_0000115 rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that effectively converts an L-phenylalanine residue to 3-hydroxy-L-phenylalanine.</obo:IAO_0000115>
         <mod:DiffAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">16.0</mod:DiffAvg>
         <mod:DiffFormula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">C 0 H 0 N 0 O 1</mod:DiffFormula>
@@ -76021,12 +76021,15 @@
         <mod:Source rdf:datatype="http://www.w3.org/2001/XMLSchema#string">natural</mod:Source>
         <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">uniprot.ptm:PTM-0346</oboInOwl:hasDbXref>
         <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">(2S,3S)-2-amino-3-hydroxy-3-phenylpropanoic acid</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">(S)-2-amino-3-(3-hydroxyphenyl)propanoic acid</oboInOwl:hasExactSynonym>
         <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">3-hydoxyphenylalanine</oboInOwl:hasExactSynonym>
         <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">3-hydroxy-L-phenylalanine</oboInOwl:hasExactSynonym>
         <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">3-phenyl-L-serine</oboInOwl:hasExactSynonym>
         <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">3HyPhe</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">L-m-Tyrosine</oboInOwl:hasExactSynonym>
         <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">L-threo-3-phenylserine</oboInOwl:hasExactSynonym>
         <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">MOD_RES 3-hydroxyphenylalanine</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Meta-Tyrosine</oboInOwl:hasExactSynonym>
         <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">beta-hydroxyphenylalanine</oboInOwl:hasExactSynonym>
         <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">beta-phenylserine</oboInOwl:hasExactSynonym>
         <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">hydroxylationf</oboInOwl:hasExactSynonym>
@@ -76054,6 +76057,12 @@
         <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">(2S,3S)-2-amino-3-hydroxy-3-phenylpropanoic acid</owl:annotatedTarget>
         <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#RESID-systematic"/>
     </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_01385"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">(S)-2-amino-3-(3-hydroxyphenyl)propanoic acid</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-label"/>
+    </owl:Axiom>
     <owl:Axiom>
         <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_01385"/>
         <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
@@ -76078,6 +76087,12 @@
         <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">3HyPhe</owl:annotatedTarget>
         <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-label"/>
     </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_01385"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">L-m-Tyrosine</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-label"/>
+    </owl:Axiom>
     <owl:Axiom>
         <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_01385"/>
         <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
@@ -76090,6 +76105,12 @@
         <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">MOD_RES 3-hydroxyphenylalanine</owl:annotatedTarget>
         <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#UniProt-feature"/>
     </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_01385"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Meta-Tyrosine</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-label"/>
+    </owl:Axiom>
     <owl:Axiom>
         <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_01385"/>
         <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
@@ -110173,6 +110194,772 @@
         <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">ModDAsn</owl:annotatedTarget>
         <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-label"/>
     </owl:Axiom>
+    
+
+
+    <!-- http://purl.obolibrary.org/obo/MOD_02098 -->
+
+    <owl:Class rdf:about="http://purl.obolibrary.org/obo/MOD_02098">
+        <obo:IAO_0000115 rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A chemical transformation driven by a radical reaction.</obo:IAO_0000115>
+        <oboInOwl:hasOBONamespace rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PSI-MOD</oboInOwl:hasOBONamespace>
+        <oboInOwl:id rdf:datatype="http://www.w3.org/2001/XMLSchema#string">MOD:02098</oboInOwl:id>
+        <rdfs:label rdf:datatype="http://www.w3.org/2001/XMLSchema#string">residue modified by radical mechanism</rdfs:label>
+    </owl:Class>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02098"/>
+        <owl:annotatedProperty rdf:resource="http://purl.obolibrary.org/obo/IAO_0000115"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A chemical transformation driven by a radical reaction.</owl:annotatedTarget>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PubMed:14670063</oboInOwl:hasDbXref>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">doi:https://pubs.acs.org/doi/10.1021/ac035104h</oboInOwl:hasDbXref>
+    </owl:Axiom>
+    
+
+
+    <!-- http://purl.obolibrary.org/obo/MOD_02099 -->
+
+    <owl:Class rdf:about="http://purl.obolibrary.org/obo/MOD_02099">
+        <rdfs:subClassOf rdf:resource="http://purl.obolibrary.org/obo/MOD_02098"/>
+        <obo:IAO_0000115 rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A hydroxyl substition induced by a radical reaction.</obo:IAO_0000115>
+        <oboInOwl:hasOBONamespace rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PSI-MOD</oboInOwl:hasOBONamespace>
+        <oboInOwl:id rdf:datatype="http://www.w3.org/2001/XMLSchema#string">MOD:02099</oboInOwl:id>
+        <rdfs:label rdf:datatype="http://www.w3.org/2001/XMLSchema#string">residue modified by radical hydroxylation</rdfs:label>
+    </owl:Class>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02099"/>
+        <owl:annotatedProperty rdf:resource="http://purl.obolibrary.org/obo/IAO_0000115"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A hydroxyl substition induced by a radical reaction.</owl:annotatedTarget>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PubMed:17683160</oboInOwl:hasDbXref>
+    </owl:Axiom>
+    
+
+
+    <!-- http://purl.obolibrary.org/obo/MOD_02100 -->
+
+    <owl:Class rdf:about="http://purl.obolibrary.org/obo/MOD_02100">
+        <rdfs:subClassOf rdf:resource="http://purl.obolibrary.org/obo/MOD_00909"/>
+        <rdfs:subClassOf rdf:resource="http://purl.obolibrary.org/obo/MOD_02099"/>
+        <obo:IAO_0000115 rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that effectively transforms an L-histidine residue to N2-formyl asparagine</obo:IAO_0000115>
+        <mod:DiffAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">4.97</mod:DiffAvg>
+        <mod:DiffFormula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">H -1 C -1 N -1 O 2</mod:DiffFormula>
+        <mod:DiffMono rdf:datatype="http://www.w3.org/2001/XMLSchema#float">4.97893</mod:DiffMono>
+        <mod:Formula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">C 5 H 6 N 2 O 3</mod:Formula>
+        <mod:MassAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">142.04</mod:MassAvg>
+        <mod:MassMono rdf:datatype="http://www.w3.org/2001/XMLSchema#float">142.03784</mod:MassMono>
+        <mod:Origin rdf:datatype="http://www.w3.org/2001/XMLSchema#string">H</mod:Origin>
+        <mod:Source rdf:datatype="http://www.w3.org/2001/XMLSchema#string">artifact</mod:Source>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Unimod:1917</oboInOwl:hasDbXref>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">(2S)-4-amino-2-formamido-4-oxobutanoic acid</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Formylasparagine</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Nω-formyl asparagine</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasOBONamespace rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PSI-MOD</oboInOwl:hasOBONamespace>
+        <oboInOwl:id rdf:datatype="http://www.w3.org/2001/XMLSchema#string">MOD:02100</oboInOwl:id>
+        <oboInOwl:inSubset rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-slim"/>
+        <rdfs:label rdf:datatype="http://www.w3.org/2001/XMLSchema#string">N2-Formyl-L-asparagine</rdfs:label>
+    </owl:Class>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02100"/>
+        <owl:annotatedProperty rdf:resource="http://purl.obolibrary.org/obo/IAO_0000115"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that effectively transforms an L-histidine residue to N2-formyl asparagine</owl:annotatedTarget>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">doi:10.1016/0040-4039(91)80099-R</oboInOwl:hasDbXref>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">osti.article:6518101</oboInOwl:hasDbXref>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02100"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">(2S)-4-amino-2-formamido-4-oxobutanoic acid</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-label"/>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02100"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Formylasparagine</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-label"/>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02100"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Nω-formyl asparagine</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-label"/>
+    </owl:Axiom>
+    
+
+
+    <!-- http://purl.obolibrary.org/obo/MOD_02101 -->
+
+    <owl:Class rdf:about="http://purl.obolibrary.org/obo/MOD_02101">
+        <rdfs:subClassOf rdf:resource="http://purl.obolibrary.org/obo/MOD_00909"/>
+        <rdfs:subClassOf rdf:resource="http://purl.obolibrary.org/obo/MOD_02099"/>
+        <obo:IAO_0000115 rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that effectively transforms a histidine side chain to that of 2-Amino-4,5-dioxopentanoic acid</obo:IAO_0000115>
+        <mod:DiffAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">-10.04</mod:DiffAvg>
+        <mod:DiffFormula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">H -2 C -1 N -2 O 2</mod:DiffFormula>
+        <mod:DiffMono rdf:datatype="http://www.w3.org/2001/XMLSchema#float">-10.031969</mod:DiffMono>
+        <mod:Formula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">C 5 H 5 N 1 O 3</mod:Formula>
+        <mod:MassAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">127.03</mod:MassAvg>
+        <mod:MassMono rdf:datatype="http://www.w3.org/2001/XMLSchema#float">127.02694</mod:MassMono>
+        <mod:Origin rdf:datatype="http://www.w3.org/2001/XMLSchema#string">H</mod:Origin>
+        <mod:Source rdf:datatype="http://www.w3.org/2001/XMLSchema#string">artifact</mod:Source>
+        <oboInOwl:hasOBONamespace rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PSI-MOD</oboInOwl:hasOBONamespace>
+        <oboInOwl:id rdf:datatype="http://www.w3.org/2001/XMLSchema#string">MOD:02101</oboInOwl:id>
+        <oboInOwl:inSubset rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-slim"/>
+        <rdfs:label rdf:datatype="http://www.w3.org/2001/XMLSchema#string">2-Amino-4,5-dioxopentanoic acid</rdfs:label>
+    </owl:Class>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02101"/>
+        <owl:annotatedProperty rdf:resource="http://purl.obolibrary.org/obo/IAO_0000115"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that effectively transforms a histidine side chain to that of 2-Amino-4,5-dioxopentanoic acid</owl:annotatedTarget>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PubMed:14670063</oboInOwl:hasDbXref>
+    </owl:Axiom>
+    
+
+
+    <!-- http://purl.obolibrary.org/obo/MOD_02102 -->
+
+    <owl:Class rdf:about="http://purl.obolibrary.org/obo/MOD_02102">
+        <rdfs:subClassOf rdf:resource="http://purl.obolibrary.org/obo/MOD_02099"/>
+        <rdfs:subClassOf rdf:resource="http://purl.obolibrary.org/obo/MOD_02116"/>
+        <obo:IAO_0000115 rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that effectively converts a L-Phenylalanine residue to 2-hydroxy-L-phenylalanine.</obo:IAO_0000115>
+        <mod:DiffAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">16.0</mod:DiffAvg>
+        <mod:DiffFormula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">O 1</mod:DiffFormula>
+        <mod:DiffMono rdf:datatype="http://www.w3.org/2001/XMLSchema#float">15.994915</mod:DiffMono>
+        <mod:Formula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">C 9 H 9 N 1 O 2</mod:Formula>
+        <mod:MassAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">163.06</mod:MassAvg>
+        <mod:MassMono rdf:datatype="http://www.w3.org/2001/XMLSchema#float">163.06332</mod:MassMono>
+        <mod:Origin rdf:datatype="http://www.w3.org/2001/XMLSchema#string">F</mod:Origin>
+        <mod:Source rdf:datatype="http://www.w3.org/2001/XMLSchema#string">artifact</mod:Source>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Unimod:35</oboInOwl:hasDbXref>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">2-amino-3-(2-hydroxyphenyl)propanoic acid</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">DL-o-Tyrosine</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">O-Tyrosine</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">o-tyrosine</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasOBONamespace rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PSI-MOD</oboInOwl:hasOBONamespace>
+        <oboInOwl:id rdf:datatype="http://www.w3.org/2001/XMLSchema#string">MOD:02102</oboInOwl:id>
+        <oboInOwl:inSubset rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-slim"/>
+        <rdfs:label rdf:datatype="http://www.w3.org/2001/XMLSchema#string">2-hydroxy-L-phenylalanine</rdfs:label>
+    </owl:Class>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02102"/>
+        <owl:annotatedProperty rdf:resource="http://purl.obolibrary.org/obo/IAO_0000115"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that effectively converts a L-Phenylalanine residue to 2-hydroxy-L-phenylalanine.</owl:annotatedTarget>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PubMed:8509373</oboInOwl:hasDbXref>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02102"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">2-amino-3-(2-hydroxyphenyl)propanoic acid</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-label"/>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02102"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">DL-o-Tyrosine</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-label"/>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02102"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">O-Tyrosine</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-label"/>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02102"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">o-tyrosine</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-alternate"/>
+    </owl:Axiom>
+    
+
+
+    <!-- http://purl.obolibrary.org/obo/MOD_02104 -->
+
+    <owl:Class rdf:about="http://purl.obolibrary.org/obo/MOD_02104">
+        <rdfs:subClassOf rdf:resource="http://purl.obolibrary.org/obo/MOD_00914"/>
+        <rdfs:subClassOf rdf:resource="http://purl.obolibrary.org/obo/MOD_02116"/>
+        <obo:IAO_0000115 rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that effectively substitutes a hydroxy group at position 4 of L-phenylalanine</obo:IAO_0000115>
+        <mod:DiffAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">16.0</mod:DiffAvg>
+        <mod:DiffFormula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">O 1</mod:DiffFormula>
+        <mod:DiffMono rdf:datatype="http://www.w3.org/2001/XMLSchema#float">15.994915</mod:DiffMono>
+        <mod:Formula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">C 9 H 9 N 1 O 2</mod:Formula>
+        <mod:MassAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">163.18</mod:MassAvg>
+        <mod:MassMono rdf:datatype="http://www.w3.org/2001/XMLSchema#float">163.06332</mod:MassMono>
+        <mod:Origin rdf:datatype="http://www.w3.org/2001/XMLSchema#string">F</mod:Origin>
+        <mod:Source rdf:datatype="http://www.w3.org/2001/XMLSchema#string">artifact</mod:Source>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Unimod:35</oboInOwl:hasDbXref>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">(2S)-2-amino-3-(4-hydroxyphenyl)propanoic acid</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">L-Tyrosine</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">L-tyrosine</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Phe-&gt;Tyr</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasOBONamespace rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PSI-MOD</oboInOwl:hasOBONamespace>
+        <oboInOwl:id rdf:datatype="http://www.w3.org/2001/XMLSchema#string">MOD:02104</oboInOwl:id>
+        <oboInOwl:inSubset rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-slim"/>
+        <rdfs:label rdf:datatype="http://www.w3.org/2001/XMLSchema#string">4-hydroxy-L-phenylalanine</rdfs:label>
+    </owl:Class>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02104"/>
+        <owl:annotatedProperty rdf:resource="http://purl.obolibrary.org/obo/IAO_0000115"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that effectively substitutes a hydroxy group at position 4 of L-phenylalanine</owl:annotatedTarget>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PubMed:7408053</oboInOwl:hasDbXref>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02104"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">(2S)-2-amino-3-(4-hydroxyphenyl)propanoic acid</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-alternate"/>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02104"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">L-Tyrosine</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-alternate"/>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02104"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">L-tyrosine</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-alternate"/>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02104"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Phe-&gt;Tyr</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-alternate"/>
+    </owl:Axiom>
+    
+
+
+    <!-- http://purl.obolibrary.org/obo/MOD_02105 -->
+
+    <owl:Class rdf:about="http://purl.obolibrary.org/obo/MOD_02105">
+        <rdfs:subClassOf rdf:resource="http://purl.obolibrary.org/obo/MOD_00428"/>
+        <rdfs:subClassOf rdf:resource="http://purl.obolibrary.org/obo/MOD_00914"/>
+        <obo:IAO_0000115 rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that effectively converts an L-tyrosine residue to L-2&apos;,5&apos;-dihydroxyphenylalanine.</obo:IAO_0000115>
+        <mod:DiffAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">32.0</mod:DiffAvg>
+        <mod:DiffFormula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">C 0 H 0 N 0 O 1</mod:DiffFormula>
+        <mod:DiffMono rdf:datatype="http://www.w3.org/2001/XMLSchema#float">31.989828</mod:DiffMono>
+        <mod:Formula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">C 9 H 9 N 1 O 3</mod:Formula>
+        <mod:MassAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">179.18</mod:MassAvg>
+        <mod:MassMono rdf:datatype="http://www.w3.org/2001/XMLSchema#float">179.05824</mod:MassMono>
+        <mod:Origin rdf:datatype="http://www.w3.org/2001/XMLSchema#string">F</mod:Origin>
+        <mod:Source rdf:datatype="http://www.w3.org/2001/XMLSchema#string">artifact</mod:Source>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">2,5-Dihydroxyphenylalanine</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">2,5-Dioxyphenylalanine</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">2-amino-3-(2,5-dihydroxyphenyl)propanoic acid</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasOBONamespace rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PSI-MOD</oboInOwl:hasOBONamespace>
+        <oboInOwl:id rdf:datatype="http://www.w3.org/2001/XMLSchema#string">MOD:02105</oboInOwl:id>
+        <oboInOwl:inSubset rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-slim"/>
+        <rdfs:label rdf:datatype="http://www.w3.org/2001/XMLSchema#string">L-2,5-dihydroxyphenylalanine (Phe)</rdfs:label>
+    </owl:Class>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02105"/>
+        <owl:annotatedProperty rdf:resource="http://purl.obolibrary.org/obo/IAO_0000115"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that effectively converts an L-tyrosine residue to L-2&apos;,5&apos;-dihydroxyphenylalanine.</owl:annotatedTarget>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">doi:10.1016/j.radphyschem.2003.11.008</oboInOwl:hasDbXref>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02105"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">2,5-Dihydroxyphenylalanine</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-label"/>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02105"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">2,5-Dioxyphenylalanine</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-label"/>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02105"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">2-amino-3-(2,5-dihydroxyphenyl)propanoic acid</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-label"/>
+    </owl:Axiom>
+    
+
+
+    <!-- http://purl.obolibrary.org/obo/MOD_02106 -->
+
+    <owl:Class rdf:about="http://purl.obolibrary.org/obo/MOD_02106">
+        <rdfs:subClassOf rdf:resource="http://purl.obolibrary.org/obo/MOD_01622"/>
+        <obo:IAO_0000115 rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that effectively converts an L-tryptophan residue to a 4-hydroxy-L-tryptophan.</obo:IAO_0000115>
+        <mod:DiffAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">16.0</mod:DiffAvg>
+        <mod:DiffFormula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">C 0 H 0 N 0 O 1</mod:DiffFormula>
+        <mod:DiffMono rdf:datatype="http://www.w3.org/2001/XMLSchema#float">15.994915</mod:DiffMono>
+        <mod:Formula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">C 11 H 10 N 2 O 2</mod:Formula>
+        <mod:MassAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">202.21</mod:MassAvg>
+        <mod:MassMono rdf:datatype="http://www.w3.org/2001/XMLSchema#float">202.07423</mod:MassMono>
+        <mod:Origin rdf:datatype="http://www.w3.org/2001/XMLSchema#string">W</mod:Origin>
+        <mod:Source rdf:datatype="http://www.w3.org/2001/XMLSchema#string">hypothetical</mod:Source>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">(S)-2-Amino-3-(4-hydroxy-1H-indol-3-yl)propanoic acid</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasOBONamespace rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PSI-MOD</oboInOwl:hasOBONamespace>
+        <oboInOwl:id rdf:datatype="http://www.w3.org/2001/XMLSchema#string">MOD:02106</oboInOwl:id>
+        <rdfs:label rdf:datatype="http://www.w3.org/2001/XMLSchema#string">4-hydroxy-L-tryptophan</rdfs:label>
+    </owl:Class>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02106"/>
+        <owl:annotatedProperty rdf:resource="http://purl.obolibrary.org/obo/IAO_0000115"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that effectively converts an L-tryptophan residue to a 4-hydroxy-L-tryptophan.</owl:annotatedTarget>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PMID:32911085</oboInOwl:hasDbXref>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02106"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">(S)-2-Amino-3-(4-hydroxy-1H-indol-3-yl)propanoic acid</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-alternate"/>
+    </owl:Axiom>
+    
+
+
+    <!-- http://purl.obolibrary.org/obo/MOD_02107 -->
+
+    <owl:Class rdf:about="http://purl.obolibrary.org/obo/MOD_02107">
+        <rdfs:subClassOf rdf:resource="http://purl.obolibrary.org/obo/MOD_01622"/>
+        <obo:IAO_0000115 rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that effectively converts an L-tryptophan residue to a 5-hydroxy-L-tryptophan.</obo:IAO_0000115>
+        <mod:DiffAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">16.0</mod:DiffAvg>
+        <mod:DiffFormula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">C 0 H 0 N 0 O 1</mod:DiffFormula>
+        <mod:DiffMono rdf:datatype="http://www.w3.org/2001/XMLSchema#float">15.994915</mod:DiffMono>
+        <mod:Formula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">C 11 H 10 N 2 O 2</mod:Formula>
+        <mod:MassAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">202.21</mod:MassAvg>
+        <mod:MassMono rdf:datatype="http://www.w3.org/2001/XMLSchema#float">202.07423</mod:MassMono>
+        <mod:Origin rdf:datatype="http://www.w3.org/2001/XMLSchema#string">W</mod:Origin>
+        <mod:Source rdf:datatype="http://www.w3.org/2001/XMLSchema#string">hypothetical</mod:Source>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">(S)-2-Amino-3-(5-hydroxy-1H-indol-3-yl)propanoic acid</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasOBONamespace rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PSI-MOD</oboInOwl:hasOBONamespace>
+        <oboInOwl:id rdf:datatype="http://www.w3.org/2001/XMLSchema#string">MOD:02107</oboInOwl:id>
+        <rdfs:label rdf:datatype="http://www.w3.org/2001/XMLSchema#string">5-hydroxy-L-tryptophan</rdfs:label>
+    </owl:Class>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02107"/>
+        <owl:annotatedProperty rdf:resource="http://purl.obolibrary.org/obo/IAO_0000115"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that effectively converts an L-tryptophan residue to a 5-hydroxy-L-tryptophan.</owl:annotatedTarget>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PMID:32911085</oboInOwl:hasDbXref>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02107"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">(S)-2-Amino-3-(5-hydroxy-1H-indol-3-yl)propanoic acid</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-alternate"/>
+    </owl:Axiom>
+    
+
+
+    <!-- http://purl.obolibrary.org/obo/MOD_02108 -->
+
+    <owl:Class rdf:about="http://purl.obolibrary.org/obo/MOD_02108">
+        <rdfs:subClassOf rdf:resource="http://purl.obolibrary.org/obo/MOD_01622"/>
+        <obo:IAO_0000115 rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that effectively converts an L-tryptophan residue to a 6-hydroxy-L-tryptophan.</obo:IAO_0000115>
+        <mod:DiffAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">16.0</mod:DiffAvg>
+        <mod:DiffFormula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">C 0 H 0 N 0 O 1</mod:DiffFormula>
+        <mod:DiffMono rdf:datatype="http://www.w3.org/2001/XMLSchema#float">15.994915</mod:DiffMono>
+        <mod:Formula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">C 11 H 10 N 2 O 2</mod:Formula>
+        <mod:MassAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">202.21</mod:MassAvg>
+        <mod:MassMono rdf:datatype="http://www.w3.org/2001/XMLSchema#float">202.07423</mod:MassMono>
+        <mod:Origin rdf:datatype="http://www.w3.org/2001/XMLSchema#string">W</mod:Origin>
+        <mod:Source rdf:datatype="http://www.w3.org/2001/XMLSchema#string">hypothetical</mod:Source>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">(S)-2-Amino-3-(4-hydroxy-1H-indol-3-yl)propanoic acid</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasOBONamespace rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PSI-MOD</oboInOwl:hasOBONamespace>
+        <oboInOwl:id rdf:datatype="http://www.w3.org/2001/XMLSchema#string">MOD:02108</oboInOwl:id>
+        <rdfs:label rdf:datatype="http://www.w3.org/2001/XMLSchema#string">6-hydroxy-L-tryptophan</rdfs:label>
+    </owl:Class>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02108"/>
+        <owl:annotatedProperty rdf:resource="http://purl.obolibrary.org/obo/IAO_0000115"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that effectively converts an L-tryptophan residue to a 6-hydroxy-L-tryptophan.</owl:annotatedTarget>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PMID:32911085</oboInOwl:hasDbXref>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02108"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">(S)-2-Amino-3-(4-hydroxy-1H-indol-3-yl)propanoic acid</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-alternate"/>
+    </owl:Axiom>
+    
+
+
+    <!-- http://purl.obolibrary.org/obo/MOD_02109 -->
+
+    <owl:Class rdf:about="http://purl.obolibrary.org/obo/MOD_02109">
+        <rdfs:subClassOf rdf:resource="http://purl.obolibrary.org/obo/MOD_01622"/>
+        <obo:IAO_0000115 rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that effectively converts an L-tryptophan residue to a oxindolylalanine.</obo:IAO_0000115>
+        <mod:DiffAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">16.0</mod:DiffAvg>
+        <mod:DiffFormula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">C 0 H 0 N 0 O 1</mod:DiffFormula>
+        <mod:DiffMono rdf:datatype="http://www.w3.org/2001/XMLSchema#float">15.994915</mod:DiffMono>
+        <mod:Formula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">C 11 H 10 N 2 O 2</mod:Formula>
+        <mod:MassAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">202.21</mod:MassAvg>
+        <mod:MassMono rdf:datatype="http://www.w3.org/2001/XMLSchema#float">202.07423</mod:MassMono>
+        <mod:Origin rdf:datatype="http://www.w3.org/2001/XMLSchema#string">W</mod:Origin>
+        <mod:Source rdf:datatype="http://www.w3.org/2001/XMLSchema#string">hypothetical</mod:Source>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">2-amino-3-(2-oxoindolin-3-yl)propanoic acid</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Oxindolyl-L-alanine</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasOBONamespace rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PSI-MOD</oboInOwl:hasOBONamespace>
+        <oboInOwl:id rdf:datatype="http://www.w3.org/2001/XMLSchema#string">MOD:02109</oboInOwl:id>
+        <rdfs:label rdf:datatype="http://www.w3.org/2001/XMLSchema#string">oxindolylalanine</rdfs:label>
+    </owl:Class>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02109"/>
+        <owl:annotatedProperty rdf:resource="http://purl.obolibrary.org/obo/IAO_0000115"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that effectively converts an L-tryptophan residue to a oxindolylalanine.</owl:annotatedTarget>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PMID:32911085</oboInOwl:hasDbXref>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02109"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">2-amino-3-(2-oxoindolin-3-yl)propanoic acid</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-alternate"/>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02109"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Oxindolyl-L-alanine</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-alternate"/>
+    </owl:Axiom>
+    
+
+
+    <!-- http://purl.obolibrary.org/obo/MOD_02110 -->
+
+    <owl:Class rdf:about="http://purl.obolibrary.org/obo/MOD_02110">
+        <rdfs:subClassOf rdf:resource="http://purl.obolibrary.org/obo/MOD_01024"/>
+        <obo:IAO_0000115 rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that effectively converts an L-proline residue to 5-hydroxy-L-proline</obo:IAO_0000115>
+        <mod:DiffAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">16.0</mod:DiffAvg>
+        <mod:DiffFormula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">C 0 H 0 N 0 O 1</mod:DiffFormula>
+        <mod:DiffMono rdf:datatype="http://www.w3.org/2001/XMLSchema#float">15.994915</mod:DiffMono>
+        <mod:Formula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">C 5 H 7 N 1 O 2</mod:Formula>
+        <mod:MassAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">113.12</mod:MassAvg>
+        <mod:MassMono rdf:datatype="http://www.w3.org/2001/XMLSchema#float">113.047676</mod:MassMono>
+        <mod:Origin rdf:datatype="http://www.w3.org/2001/XMLSchema#string">P</mod:Origin>
+        <mod:Source rdf:datatype="http://www.w3.org/2001/XMLSchema#string">natural</mod:Source>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">(2S,5S)-5-hydroxypyrrolidine-2-carboxylic acid</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasOBONamespace rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PSI-MOD</oboInOwl:hasOBONamespace>
+        <oboInOwl:id rdf:datatype="http://www.w3.org/2001/XMLSchema#string">MOD:02110</oboInOwl:id>
+        <oboInOwl:inSubset rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-slim"/>
+        <rdfs:label rdf:datatype="http://www.w3.org/2001/XMLSchema#string">5-hydroxy-L-proline</rdfs:label>
+    </owl:Class>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02110"/>
+        <owl:annotatedProperty rdf:resource="http://purl.obolibrary.org/obo/IAO_0000115"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that effectively converts an L-proline residue to 5-hydroxy-L-proline</owl:annotatedTarget>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">ChEBI:18095</oboInOwl:hasDbXref>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PubMed:11292863</oboInOwl:hasDbXref>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PubMed:2400108</oboInOwl:hasDbXref>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PubMed:3734192</oboInOwl:hasDbXref>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">RESID:AA0030</oboInOwl:hasDbXref>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02110"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">(2S,5S)-5-hydroxypyrrolidine-2-carboxylic acid</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-alternate"/>
+    </owl:Axiom>
+    
+
+
+    <!-- http://purl.obolibrary.org/obo/MOD_02111 -->
+
+    <owl:Class rdf:about="http://purl.obolibrary.org/obo/MOD_02111">
+        <rdfs:subClassOf rdf:resource="http://purl.obolibrary.org/obo/MOD_01411"/>
+        <obo:IAO_0000115 rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that effectively converts an L-leucine residue to a (2S,4S)-5-hydroxyleucine.</obo:IAO_0000115>
+        <mod:DiffAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">16.0</mod:DiffAvg>
+        <mod:DiffFormula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">C 0 H 0 N 0 O 1</mod:DiffFormula>
+        <mod:DiffMono rdf:datatype="http://www.w3.org/2001/XMLSchema#float">15.994915</mod:DiffMono>
+        <mod:Formula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">C 6 H 11 N 1 O 2</mod:Formula>
+        <mod:MassAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">129.16</mod:MassAvg>
+        <mod:MassMono rdf:datatype="http://www.w3.org/2001/XMLSchema#float">129.07898</mod:MassMono>
+        <mod:Origin rdf:datatype="http://www.w3.org/2001/XMLSchema#string">L</mod:Origin>
+        <mod:Source rdf:datatype="http://www.w3.org/2001/XMLSchema#string">artifact</mod:Source>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">(2S,4S)-2-amino-5-hydroxy-4-methylpentanoic acid</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasOBONamespace rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PSI-MOD</oboInOwl:hasOBONamespace>
+        <oboInOwl:id rdf:datatype="http://www.w3.org/2001/XMLSchema#string">MOD:02111</oboInOwl:id>
+        <rdfs:label rdf:datatype="http://www.w3.org/2001/XMLSchema#string">(2S,4S)-5-hydroxyleucine</rdfs:label>
+    </owl:Class>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02111"/>
+        <owl:annotatedProperty rdf:resource="http://purl.obolibrary.org/obo/IAO_0000115"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that effectively converts an L-leucine residue to a (2S,4S)-5-hydroxyleucine.</owl:annotatedTarget>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PubMed:9164839</oboInOwl:hasDbXref>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02111"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">(2S,4S)-2-amino-5-hydroxy-4-methylpentanoic acid</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-alternate"/>
+    </owl:Axiom>
+    
+
+
+    <!-- http://purl.obolibrary.org/obo/MOD_02112 -->
+
+    <owl:Class rdf:about="http://purl.obolibrary.org/obo/MOD_02112">
+        <rdfs:subClassOf rdf:resource="http://purl.obolibrary.org/obo/MOD_00918"/>
+        <obo:IAO_0000115 rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that converts an L-tryptophan residue to 4,5-Dihydroxytryptophan.</obo:IAO_0000115>
+        <mod:DiffAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">32.0</mod:DiffAvg>
+        <mod:DiffFormula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">O 2</mod:DiffFormula>
+        <mod:DiffMono rdf:datatype="http://www.w3.org/2001/XMLSchema#float">31.989828</mod:DiffMono>
+        <mod:Formula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">C 11 H 10 N 2 O 3</mod:Formula>
+        <mod:MassAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">218.21</mod:MassAvg>
+        <mod:MassMono rdf:datatype="http://www.w3.org/2001/XMLSchema#float">218.06914</mod:MassMono>
+        <mod:Origin rdf:datatype="http://www.w3.org/2001/XMLSchema#string">W</mod:Origin>
+        <mod:Source rdf:datatype="http://www.w3.org/2001/XMLSchema#string">hypothetical</mod:Source>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Unimod:425</oboInOwl:hasDbXref>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">(2S)-2-amino-3-(4,5-dihydroxy-1H-indol-3-yl)propanoic acid</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Double oxidation of Trp</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasOBONamespace rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PSI-MOD</oboInOwl:hasOBONamespace>
+        <oboInOwl:hasRelatedSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Dioxidation</oboInOwl:hasRelatedSynonym>
+        <oboInOwl:hasRelatedSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">dihydroxy</oboInOwl:hasRelatedSynonym>
+        <oboInOwl:id rdf:datatype="http://www.w3.org/2001/XMLSchema#string">MOD:02112</oboInOwl:id>
+        <oboInOwl:inSubset rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-slim"/>
+        <rdfs:label rdf:datatype="http://www.w3.org/2001/XMLSchema#string">4,5-Dihydroxytryptophan</rdfs:label>
+    </owl:Class>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02112"/>
+        <owl:annotatedProperty rdf:resource="http://purl.obolibrary.org/obo/IAO_0000115"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that converts an L-tryptophan residue to 4,5-Dihydroxytryptophan.</owl:annotatedTarget>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PubMed:16046449</oboInOwl:hasDbXref>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PubMed:30267362</oboInOwl:hasDbXref>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02112"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">(2S)-2-amino-3-(4,5-dihydroxy-1H-indol-3-yl)propanoic acid</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-alternate"/>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02112"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Double oxidation of Trp</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#DeltaMass-label"/>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02112"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasRelatedSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Dioxidation</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MS-label"/>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02112"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasRelatedSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">dihydroxy</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#Unimod-description"/>
+    </owl:Axiom>
+    
+
+
+    <!-- http://purl.obolibrary.org/obo/MOD_02113 -->
+
+    <owl:Class rdf:about="http://purl.obolibrary.org/obo/MOD_02113">
+        <rdfs:subClassOf rdf:resource="http://purl.obolibrary.org/obo/MOD_00918"/>
+        <obo:IAO_0000115 rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that converts an L-tryptophan residue to 5,6-Dihydroxytryptophan.</obo:IAO_0000115>
+        <mod:DiffAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">32.0</mod:DiffAvg>
+        <mod:DiffFormula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">O 2</mod:DiffFormula>
+        <mod:DiffMono rdf:datatype="http://www.w3.org/2001/XMLSchema#float">31.989828</mod:DiffMono>
+        <mod:Formula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">C 11 H 10 N 2 O 3</mod:Formula>
+        <mod:MassAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">218.21</mod:MassAvg>
+        <mod:MassMono rdf:datatype="http://www.w3.org/2001/XMLSchema#float">218.06914</mod:MassMono>
+        <mod:Origin rdf:datatype="http://www.w3.org/2001/XMLSchema#string">W</mod:Origin>
+        <mod:Source rdf:datatype="http://www.w3.org/2001/XMLSchema#string">hypothetical</mod:Source>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Unimod:425</oboInOwl:hasDbXref>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">(2S)-2-amino-3-(5,6-dihydroxy-1H-indol-3-yl)propanoic acid</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Double oxidation of Trp</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasOBONamespace rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PSI-MOD</oboInOwl:hasOBONamespace>
+        <oboInOwl:hasRelatedSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Dioxidation</oboInOwl:hasRelatedSynonym>
+        <oboInOwl:hasRelatedSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">dihydroxy</oboInOwl:hasRelatedSynonym>
+        <oboInOwl:id rdf:datatype="http://www.w3.org/2001/XMLSchema#string">MOD:02113</oboInOwl:id>
+        <oboInOwl:inSubset rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-slim"/>
+        <rdfs:label rdf:datatype="http://www.w3.org/2001/XMLSchema#string">5,6-Dihydroxytryptophan</rdfs:label>
+    </owl:Class>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02113"/>
+        <owl:annotatedProperty rdf:resource="http://purl.obolibrary.org/obo/IAO_0000115"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that converts an L-tryptophan residue to 5,6-Dihydroxytryptophan.</owl:annotatedTarget>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PubMed:16046449</oboInOwl:hasDbXref>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PubMed:30267362</oboInOwl:hasDbXref>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02113"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">(2S)-2-amino-3-(5,6-dihydroxy-1H-indol-3-yl)propanoic acid</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-alternate"/>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02113"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Double oxidation of Trp</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#DeltaMass-label"/>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02113"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasRelatedSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Dioxidation</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MS-label"/>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02113"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasRelatedSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">dihydroxy</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#Unimod-description"/>
+    </owl:Axiom>
+    
+
+
+    <!-- http://purl.obolibrary.org/obo/MOD_02114 -->
+
+    <owl:Class rdf:about="http://purl.obolibrary.org/obo/MOD_02114">
+        <rdfs:subClassOf rdf:resource="http://purl.obolibrary.org/obo/MOD_00918"/>
+        <obo:IAO_0000115 rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that converts an L-tryptophan residue to 5,7-Dihydroxytryptophan.</obo:IAO_0000115>
+        <mod:DiffAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">32.0</mod:DiffAvg>
+        <mod:DiffFormula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">O 2</mod:DiffFormula>
+        <mod:DiffMono rdf:datatype="http://www.w3.org/2001/XMLSchema#float">31.989828</mod:DiffMono>
+        <mod:Formula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">C 11 H 10 N 2 O 3</mod:Formula>
+        <mod:MassAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">218.21</mod:MassAvg>
+        <mod:MassMono rdf:datatype="http://www.w3.org/2001/XMLSchema#float">218.06914</mod:MassMono>
+        <mod:Origin rdf:datatype="http://www.w3.org/2001/XMLSchema#string">W</mod:Origin>
+        <mod:Source rdf:datatype="http://www.w3.org/2001/XMLSchema#string">hypothetical</mod:Source>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Unimod:425</oboInOwl:hasDbXref>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">(2S)-2-amino-3-(5,7-dihydroxy-1H-indol-3-yl)propanoic acid</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Double oxidation of Trp</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasOBONamespace rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PSI-MOD</oboInOwl:hasOBONamespace>
+        <oboInOwl:hasRelatedSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Dioxidation</oboInOwl:hasRelatedSynonym>
+        <oboInOwl:hasRelatedSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">dihydroxy</oboInOwl:hasRelatedSynonym>
+        <oboInOwl:id rdf:datatype="http://www.w3.org/2001/XMLSchema#string">MOD:02114</oboInOwl:id>
+        <oboInOwl:inSubset rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-slim"/>
+        <rdfs:label rdf:datatype="http://www.w3.org/2001/XMLSchema#string">5,7-Dihydroxytryptophan</rdfs:label>
+    </owl:Class>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02114"/>
+        <owl:annotatedProperty rdf:resource="http://purl.obolibrary.org/obo/IAO_0000115"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that converts an L-tryptophan residue to 5,7-Dihydroxytryptophan.</owl:annotatedTarget>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PubMed:16046449</oboInOwl:hasDbXref>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PubMed:30267362</oboInOwl:hasDbXref>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02114"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">(2S)-2-amino-3-(5,7-dihydroxy-1H-indol-3-yl)propanoic acid</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-alternate"/>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02114"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Double oxidation of Trp</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#DeltaMass-label"/>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02114"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasRelatedSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Dioxidation</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MS-label"/>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02114"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasRelatedSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">dihydroxy</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#Unimod-description"/>
+    </owl:Axiom>
+    
+
+
+    <!-- http://purl.obolibrary.org/obo/MOD_02115 -->
+
+    <owl:Class rdf:about="http://purl.obolibrary.org/obo/MOD_02115">
+        <rdfs:subClassOf rdf:resource="http://purl.obolibrary.org/obo/MOD_00918"/>
+        <obo:IAO_0000115 rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that converts an L-tryptophan residue to dioxindolylalanine.</obo:IAO_0000115>
+        <mod:DiffAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">32.0</mod:DiffAvg>
+        <mod:DiffFormula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">O 2</mod:DiffFormula>
+        <mod:DiffMono rdf:datatype="http://www.w3.org/2001/XMLSchema#float">31.989828</mod:DiffMono>
+        <mod:Formula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">C 11 H 10 N 2 O 3</mod:Formula>
+        <mod:MassAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">218.21</mod:MassAvg>
+        <mod:MassMono rdf:datatype="http://www.w3.org/2001/XMLSchema#float">218.06914</mod:MassMono>
+        <mod:Origin rdf:datatype="http://www.w3.org/2001/XMLSchema#string">W</mod:Origin>
+        <mod:Source rdf:datatype="http://www.w3.org/2001/XMLSchema#string">artifact</mod:Source>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Unimod:425</oboInOwl:hasDbXref>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">(2S)-2-amino-3-(3-hydroxy-2-oxo-1H-indol-3-yl)propanoic acid</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">(alphaS)-alpha-Amino-2,3-dihydro-3-hydroxy-2-oxo-1H-indole-3-propanoic acid</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Dioxindolyl-L-alanine</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasExactSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Double oxidation of Trp</oboInOwl:hasExactSynonym>
+        <oboInOwl:hasOBONamespace rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PSI-MOD</oboInOwl:hasOBONamespace>
+        <oboInOwl:hasRelatedSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Dioxidation</oboInOwl:hasRelatedSynonym>
+        <oboInOwl:hasRelatedSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">dihydroxy</oboInOwl:hasRelatedSynonym>
+        <oboInOwl:id rdf:datatype="http://www.w3.org/2001/XMLSchema#string">MOD:02115</oboInOwl:id>
+        <oboInOwl:inSubset rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-slim"/>
+        <rdfs:label rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Dioxindolylalanine</rdfs:label>
+    </owl:Class>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02115"/>
+        <owl:annotatedProperty rdf:resource="http://purl.obolibrary.org/obo/IAO_0000115"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that converts an L-tryptophan residue to dioxindolylalanine.</owl:annotatedTarget>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PubMed:10554268</oboInOwl:hasDbXref>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PubMed:32911085</oboInOwl:hasDbXref>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02115"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">(2S)-2-amino-3-(3-hydroxy-2-oxo-1H-indol-3-yl)propanoic acid</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-alternate"/>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02115"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">(alphaS)-alpha-Amino-2,3-dihydro-3-hydroxy-2-oxo-1H-indole-3-propanoic acid</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-alternate"/>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02115"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Dioxindolyl-L-alanine</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-alternate"/>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02115"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasExactSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Double oxidation of Trp</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#DeltaMass-label"/>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02115"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasRelatedSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Dioxidation</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MS-label"/>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02115"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasRelatedSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">dihydroxy</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#Unimod-description"/>
+    </owl:Axiom>
+    
+
+
+    <!-- http://purl.obolibrary.org/obo/MOD_02116 -->
+
+    <owl:Class rdf:about="http://purl.obolibrary.org/obo/MOD_02116">
+        <rdfs:subClassOf rdf:resource="http://purl.obolibrary.org/obo/MOD_00425"/>
+        <rdfs:subClassOf rdf:resource="http://purl.obolibrary.org/obo/MOD_00914"/>
+        <obo:IAO_0000115 rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that effectively converts an L-phenylalanine residue to a monohydroxylated phenylalanine.</obo:IAO_0000115>
+        <mod:DiffAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">16.0</mod:DiffAvg>
+        <mod:DiffFormula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">C 0 H 0 N 0 O 1</mod:DiffFormula>
+        <mod:DiffMono rdf:datatype="http://www.w3.org/2001/XMLSchema#float">15.994915</mod:DiffMono>
+        <mod:Formula rdf:datatype="http://www.w3.org/2001/XMLSchema#string">C 6 H 12 N 2 O 2</mod:Formula>
+        <mod:MassAvg rdf:datatype="http://www.w3.org/2001/XMLSchema#float">144.17</mod:MassAvg>
+        <mod:MassMono rdf:datatype="http://www.w3.org/2001/XMLSchema#float">144.08987</mod:MassMono>
+        <mod:Origin rdf:datatype="http://www.w3.org/2001/XMLSchema#string">F</mod:Origin>
+        <mod:Source rdf:datatype="http://www.w3.org/2001/XMLSchema#string">artifact</mod:Source>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Unimod:35</oboInOwl:hasDbXref>
+        <oboInOwl:hasOBONamespace rdf:datatype="http://www.w3.org/2001/XMLSchema#string">PSI-MOD</oboInOwl:hasOBONamespace>
+        <oboInOwl:hasRelatedSynonym rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Oxidation</oboInOwl:hasRelatedSynonym>
+        <oboInOwl:id rdf:datatype="http://www.w3.org/2001/XMLSchema#string">MOD:02116</oboInOwl:id>
+        <oboInOwl:inSubset rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MOD-slim"/>
+        <rdfs:label rdf:datatype="http://www.w3.org/2001/XMLSchema#string">monohydroxylated phenylalanine</rdfs:label>
+    </owl:Class>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02116"/>
+        <owl:annotatedProperty rdf:resource="http://purl.obolibrary.org/obo/IAO_0000115"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">A protein modification that effectively converts an L-phenylalanine residue to a monohydroxylated phenylalanine.</owl:annotatedTarget>
+        <oboInOwl:hasDbXref rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Unimod:35#F</oboInOwl:hasDbXref>
+    </owl:Axiom>
+    <owl:Axiom>
+        <owl:annotatedSource rdf:resource="http://purl.obolibrary.org/obo/MOD_02116"/>
+        <owl:annotatedProperty rdf:resource="http://www.geneontology.org/formats/oboInOwl#hasRelatedSynonym"/>
+        <owl:annotatedTarget rdf:datatype="http://www.w3.org/2001/XMLSchema#string">Oxidation</owl:annotatedTarget>
+        <oboInOwl:hasSynonymType rdf:resource="http://purl.obolibrary.org/obo/mod#PSI-MS-label"/>
+    </owl:Axiom>
 </rdf:RDF>