EC 1.8.5.5     
Accepted name: thiosulfate reductase (quinone)
Reaction: sulfite + hydrogen sulfide + a quinone = thiosulfate + a quinol
Other name(s): phsABC (gene names)
Systematic name: sulfite,hydrogen sulfide:quinone oxidoreductase
Comments: The enzyme, characterized from the bacterium Salmonella enterica, is similar to EC 1.17.5.3, formate dehydrogenase-N. It contains a molybdopterin-guanine dinucleotide, five [4Fe-4S] clusters and two heme b groups. The reaction occurs in vivo in the direction of thiosulfate disproportionation, which is highly endergonic. It is driven by the proton motive force that occurs across the cytoplasmic membrane.
References:
1.  Kwan, H.S. and Barrett, E.L. Map locations and functions of Salmonella typhimurium men genes. J. Bacteriol. 159 (1984) 1090–1092. [PMID: 6384182]
2.  Clark, M.A. and Barrett, E.L. The phs gene and hydrogen sulfide production by Salmonella typhimurium. J. Bacteriol. 169 (1987) 2391–2397. [PMID: 3108233]
3.  Alami, N. and Hallenbeck, P.C. Cloning and characterization of a gene cluster, phsBCDEF, necessary for the production of hydrogen sulfide from thiosulfate by Salmonella typhimurium. Gene 156 (1995) 53–57. [PMID: 7737516]
4.  Heinzinger, N.K., Fujimoto, S.Y., Clark, M.A., Moreno, M.S. and Barrett, E.L. Sequence analysis of the phs operon in Salmonella typhimurium and the contribution of thiosulfate reduction to anaerobic energy metabolism. J. Bacteriol. 177 (1995) 2813–2820. [PMID: 7751291]
5.  Stoffels, L., Krehenbrink, M., Berks, B.C. and Unden, G. Thiosulfate reduction in Salmonella enterica is driven by the proton motive force. J. Bacteriol. 194 (2012) 475–485. [PMID: 22081391]
[EC 1.8.5.5 created 2016, modified 2017]