Rhodanese from Thiobacillus A2: catalysis of reactions of thiosulphate with dihydrolipoate and dihydrolipoamide.
Rhodanese (thiosulphate:cyanide sulphurtransferase EC.2.8.1.1) was purified 25- to 30-fold from thiosulphate-grown Thiobacillus A2. It exhibited a pH optimum between pH 10-2 and 10-4 and apparent Km values of 0-36 mM-Na2S2O3 and 17 mM-KCN. Ultraviolet spectrophotometry and thin-layer chromatography showed that the enzyme catalysed the reaction of S2O3(2-) with dihydrolipoic acid or dihydrolipoamide, producing alpha-lipoate or lipoamide, with the intermediate production of the persulphides of dihydrolipoate and dihydrolipoamide, which were demonstrated chromatographically. This is the first demonstration of catalysis by a thiobacillus rhodanese of reactions which are likely to be physiologically important in the oxidative dissimilation of thiosulphate by a central energy-conserving pathway.
D000577:Amides / Q000096:biosynthesis / Q000378:metabolism*; D002384:Catalysis; D002474:Cell-Free System; D006863:Hydrogen-Ion Concentration; D013466:Sulfurtransferases / Q000378:metabolism*; D013855:Thiobacillus / Q000201:enzymology*; D008063:Thioctic Acid / Q000031:analogs & derivatives / Q000096:biosynthesis; D013884:Thiosulfate Sulfurtransferase / Q000378:metabolism*; D013885:Thiosulfates / Q000378:metabolism*
D000577:Amides; D013885:Thiosulfates; C007409:dihydrolipoamide; D008063:Thioctic Acid; D013466:Sulfurtransferases; D013884:Thiosulfate Sulfurtransferase