Reaction: 2-oxo-3-sulfanylpropanoate + reduced thioredoxin = pyruvate + hydrogen sulfide + oxidized thioredoxin (overall reaction)
(1a) 2-oxo-3-sulfanylpropanoate + [3-mercaptopyruvate sulfurtransferase]-L-cysteine = pyruvate + [3-mercaptopyruvate sulfurtransferase]-S-sulfanyl-L-cysteine
(1b) [3-mercaptopyruvate sulfurtransferase]-S-sulfanyl-L-cysteine + reduced thioredoxin = hydrogen sulfide + [3-mercaptopyruvate sulfurtransferase]-L-cysteine + oxidized thioredoxin
Glossary: 2-oxo-3-sulfanylpropanoate = 3-mercaptopyruvate (deprecated)
Other name(s): β-mercaptopyruvate sulfurtransferase; TUM1 (gene name); MPST (gene name); 3-mercaptopyruvate:cyanide sulfurtransferase
Systematic name: 3-mercaptopyruvate:sulfide sulfurtransferase
Comments: The enzyme catalyses a transsulfuration reaction from 2-oxo-3-sulfanylpropanoate to an internal cysteine residue. In the presence of a dithiol such as reduced thioredoxin or dihydrolipoate, the sulfanyl sulfur is released as hydrogen sulfide. The enzyme participates in a sulfur relay process that leads to the 2-thiolation of some tRNAs and to protein urmylation by transferring sulfur between the NFS1 cysteine desulfurase (EC 2.8.1.7) and the MOCS3 sulfurtransferase (EC 2.8.1.11).
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 9026-05-5
References:
1. Fiedler, H. and Wood, J.L. Specificity studies on the β-mercaptopyruvate-cyanide transsulfuration system. J. Biol. Chem. 222 (1956) 387-397. [PMID: 13367011]
2. Sörbo, B.H. Enzymic transfer of sulfur from mercaptopyruvate to sulfite or sulfinates. Biochem. Biophys. Acta 24 (1957) 324-329. [PMID: 13436433]
3. Hylin, J.W. and Wood, J.L. Enzymatic formation of polysulfides from mercaptopyruvate. J. Biol. Chem. 234 (1959) 2141-2144. [PMID: 13673028]
4. van den Hamer, C.J.A., Morell, A.G. and Scheinberg, H.I. A study of the copper content of β-mercaptopyruvate trans-sulfurase. J. Biol. Chem. 242 (1967) 2514-2516. [PMID: 6026243]
5. Vachek, H. and Wood, J.L. Purification and properties of mercaptopyruvate sulfur transferase of Escherichia coli. Biochim. Biophys. Acta 258 (1972) 133-146. [PMID: 4550801]
6. Nagahara, N. and Katayama, A. Post-translational regulation of mercaptopyruvate sulfurtransferase via a low redox potential cysteine-sulfenate in the maintenance of redox homeostasis. J. Biol. Chem. 280 (2005) 34569-34576. [PMID: 16107337]
7. Shibuya, N., Tanaka, M., Yoshida, M., Ogasawara, Y., Togawa, T., Ishii, K. and Kimura, H. 3-Mercaptopyruvate sulfurtransferase produces hydrogen sulfide and bound sulfane sulfur in the brain. Antioxid Redox Signal 11 (2009) 703-714. [PMID: 18855522]
8. Mikami, Y., Shibuya, N., Kimura, Y., Nagahara, N., Ogasawara, Y. and Kimura, H. Thioredoxin and dihydrolipoic acid are required for 3-mercaptopyruvate sulfurtransferase to produce hydrogen sulfide. Biochem. J. 439 (2011) 479-485. [PMID: 21732914]