derives from L-cystine (cross-link) modified L-cysteine residue reduction of disulfide crosslink in cystine to two cysteines 2.0156500339508056641 2.0199999809265136719 206.01837158203125 206.2899932861328125 MOD:00034 H 2 A protein modification that effectively reduces the disulfide bond of cystine to form two cysteine residues. PSI-MOD none MOD:00961 C 6 H 10 N 2 O 2 S 2 Cross-link 2; this modification destroys the cross-link. From DeltaMass: Treatment of cystine (cys-cys) by reducing agents such as dithiothreitol (DTT) or triscarboxyethylphosphine (TCEP) results in cleavage of the disulphide bond and reduction of the sulphur atom of each molecule to create cysteine. none hydrogenated residue