part of L-cysteine glutathione disulfide modified L-cysteine residue disulfide conjugated residue S-(cysteinyl-glycyl)-L-cysteine 176.0255584716796875 176.1699981689453125 279.034759521484375 279.329986572265625 A protein modification that effectively cross-links an L-cysteinyl-L-glycine dipeptide and an L-cysteine residue by a disulfide bond to form S-(cysteinyl-glycyl)-L-cysteine. C C 5 H 8 N 2 O 3 S 1 C 8 H 13 N 3 O 4 S 2 Glutamyl-transpeptidase cleaves glutathione into cysteinylglycine (Cys-Gly) and a Glu residue. [PubMed:28537416] MOD:02026 PSI-MOD natural