| Average Mass Shift [Da] |
Modification |
| - | Dipeptide Masses |
| - | Diketopiperazine (DKP) Formation |
| -71 | Loss of Acm group from Cysteine |
| -36 | Dehydration (2 x H2O) |
| -34 | Cysteine β-elimination (Dehydroalanine) |
| -18 | Dehydration (1 x H2O) |
| -18 | Aspartimide formation from Asp |
| -18 | Pyroglutamate or Glutarimide Formation on Glu |
| -17 | Aspartimide formation from Asn |
| -17 | Pyroglutamate or Glutarimide Formation on Gln |
| -2 | Disulfide Bond Formation; Cysteine Oxidation |
| -2 | Cysteine Sulfenamide Formation |
| -1 | Amidation of Carboxylic Group |
| 0 | Peptide Modifications With Identical Masses |
| 1 | C-Terminal Amide Group Hydrolysis |
| 1 | Hydrolysis of Asn or Gln Side Chains (Aspartimide formation) |
| 2 | Disulfide Bond (Cystine) Reduction |
| 2 | Reduction of Trp Side Chain Groupe (Indole) |
| 4 | Oxidation of Trp to Kynurenine |
| 14 | Methyl Esterification of the Carboxyl Groups |
| 14 | N-Methylation |
| 14 | Thiosulfinate Formation |
| 16 | Methionine Oxidation |
| 16 | Oxidation of Cysteine to Cysteine Sulfenic Acid |
| 16 | Oxidation of Histidine to 2-O-Histidine |
| 16 | Oxidation of Tryptophan to Oxindolylalanine (Trp to Oia) |
| 16 | Thiosulfinate Formation |
| 28 | N,N-Dimethylation |
| 30 | Thiosulfonate Formation |
| 32 | Trisulfide Bond Formation |
| 32 | Methionine Oxidation |
| 32 | Cysteine Sulfinic Acid Formation |
| 32 | Thiosulfonate Formation |
| 32 | Oxidation of Tryptophan to N-Formylkynurenine |
| 40 | Serine or Threonine Pseudoproline (Ψ-Me,MePro) |
| 42 | Acetylation |
| 44 | Incomplete Tryptophan Boc Group Removal |
| 48 | Cysteine Sulfonic Acid Formation |
| 51 | Fmoc-Cys(Acm)-OH or Fmoc-Cys(Trt)-OH Side Reaction with Piperidine |
| 56 | Peptide tert-Butylation (monoalkylated) |
| 57 | Glycine Mass Shift |
| 57 | Methionine Tert-Butylation (monoalkylated) |
| 65 | Cys Side Reaction with 4-Methylpiperidine |
| 67 | Piperidide Peptide from Asp |
| 68 | Piperidide Peptide from Asn |
| 71 | Alanine Mass Shift |
| 92 | Cysteine-EDT Adduct Formation |
| 96 | Trifluoroacetylation of -NH2 od -OH groups |
| 97 | Proline Mass Shift |
| 98 | Guanidinium Formation on Amino Group |
| 99 | Valine Mass Shift |
| 100 | tert-Butyloxycarbonyl (Boc) |
| 101 | Threonine Miss Coupling |
| 103 | Cysteine Mass Shift |
| 106 | Cys, Trp, or C-Terminys Alkylation by Wang Resin Linker: 4-Hydroxylbenzylation |
| 112 | Peptide tert-Butylation (dialkylated) |
| 113 | Isoleucine Mass Shift |
| 113 | Leucine Mass Shift |
| 114 | Asparagine Mass Shift |
| 114 | Methionine Tert-Butylation (dialkylated) |
| 115 | Aspartate Mass Shift |
| 117 | Methionine Alkylation dy DODT |
| 128 | Glutamine Mass Shift |
| 128 | Lysine Mass Shift |
| 129 | Glutamate Mass Shift |
| 131 | Methionine Mass Shift |
| 137 | Histidine Mass Shift |
| 147 | Phenylalanine Mass Shift |
| 148 | Cysteine-EDT-tBu Adduct Formation |
| 156 | Arginine Mass Shift |
| 163 | Rink amide MBHA linker Trp Alkylation |
| 163 | Tyrosine Mass Shift |
| 172 | Trp-EDT-TFA Cyclic Adduct |
| 178 | Dibenzofulvene Peptide Alkylation |
| 186 | Tryptophan Mass Shift |
| 202 | Trp, Cys, or C-Terminus Alkylation by Wang Resin Linker: 4-Trifluoroacetyoxybenzylation |
| 212 | 4-Methoxy-2,3,6-trimethylbenzenesulfonyl (Mtr) |
| 212 | Trp 4-Hydroxylbenzyl Dialkylation by Wang Resin Linker |
| 222 | Fmoc group |
| 242 | Trtylation |
| 252 | Pbf Derivative |
| 265 | Tryptophan-Pal linker Alkylation |
| 274 | Cysteine Sulfinic Acid + Trt Group Derivative |
| 308 | Trp 4-Hydroxylbenzyl and 4-Trifluoroacetyloxybenzyl Dialkylation (Wang Resin Linker) |
| 404 | Trp 4-Trifluoroacetyloxybenzyl Dialkylation (Wang Resin Linker) |
