reagent derivatized residue modified L-cysteine residue S-(acetylamino)methyl-L-cysteine 174.046295166015625 174.220001220703125 71.03711700439453125 71.0800018310546875 PSI-MOD Acm-Cys MOD:01079 From DeltaMass: (name misspelled "Acetamidomethyl Cystenyl") Average Mass: 174 Formula: C 6 H 10 O 2 N 2 S 1 Monoisotopic Mass Change: 174.046 Average Mass Change: 174.221. [These are aggregate masses, not delta masses.] See Organic Syntheses, Coll. Vol. 6, p.5 (1988); Vol. 59, p.190 (1979); http://www.orgsyn.org/orgsyn/orgsyn/prepContent.asp?prep=cv6p0005 [JSG]. S-(acetamido)methyl-L-cysteine N-(hydroxymethyl)acetamide derivatized L-cysteine C 3 H 5 N 1 O 1 C Acetamidomethyl Cystenyl none A protein modification that effectively converts an L-cysteine residue to S-[(acetylamino)methyl]-L-cysteine. artifact C 6 H 10 N 2 O 2 S 1