title: Chromogenic substrates for sulfurtransferases.
abstract: The azo dye 4-(dimethylamino)-4'-azobenzene (DAB) thiosulfonate anion can serve as a sulfur-donor substrate for rhodanese (thiosulfate: cyanide sulfurtransferase, EC 2.8.1.1) and for thiosulfate reductase (EC unassigned) with cyanide anion and GSH, respectively, as acceptor substrates. In either case, the dye product is DAB sulfinate, which differs substantially in light absorption at 500 nm. Moreover, DAB sulfinate can serve as a sulfur-acceptor substrate for rhodanese with either inorganic thiosulfate or a colorless thiosulfonate anion as donor, and this reaction provides a second chromogenic assay procedure.
mesh_terms: D001391:Azo Compounds / Q000032:analysis; D002384:Catalysis; D002863:Chromogenic Compounds; D010088:Oxidoreductases / Q000032:analysis; D050862:Oxidoreductases Acting on Sulfur Group Donors; D013053:Spectrophotometry; D013379:Substrate Specificity; D013466:Sulfurtransferases / Q000032:analysis*; D013884:Thiosulfate Sulfurtransferase / Q000032:analysis; D004124:p-Dimethylaminoazobenzene / Q000031:analogs & derivatives / Q000032:analysis
chemical_list: D001391:Azo Compounds; D002863:Chromogenic Compounds; C049199:dimethylaminoazobenzene-4-sulfinate; C100258:methyl orange; C047400:dimethylaminoazobenzene-4-thiosulfonate; D004124:p-Dimethylaminoazobenzene; D010088:Oxidoreductases; D050862:Oxidoreductases Acting on Sulfur Group Donors; D013466:Sulfurtransferases; D013884:Thiosulfate Sulfurtransferase; C022747:thiosulfate-dithiol sulfurtransferase