Transfer of persulfide sulfur from thiocystine to rhodanese.
THiocystine (bis-[2-amino-2-carboxyethyl]trisulfide) is a natural substrate for rhodanese (thiosulfate:cyanide sulfurtransferase, EC 2.8.1.1). Analogs of thiocystine were prepared by eliminating the carboxyl or amino group or by lengthening the carbon chain. Of these only homothiocystine (bis-[2-amino-2-carboxypropyl]trisulfide) had appreciable activity as a substrate. At pH 8.6, the optimum for rhodanese, transfer of sulfane sulfur to cyanide in the presence of rhodanese was nonspecific. Only the sulfane sulfur of 35S-labeled thiocystine was transferred to rhodanese. Thus, thiocystine and thiosulfate both produce a rhodanese persulfide as a stable intermediate in sulfur transfer.
D055598:Chemical Phenomena; D002621:Chemistry; D003553:Cystine / Q000031:analogs & derivatives*; D006711:Homocystine / Q000031:analogs & derivatives; D007700:Kinetics; D013379:Substrate Specificity; D013455:Sulfur; D013466:Sulfurtransferases; D013884:Thiosulfate Sulfurtransferase
C019572:thiocystine; D006711:Homocystine; D003553:Cystine; C019415:homothiocystine; D013455:Sulfur; D013466:Sulfurtransferases; D013884:Thiosulfate Sulfurtransferase