Reaction: H2 + (sulfide)n = hydrogen sulfide + (sulfide)n-1
Other name(s): sulfur reductase
Systematic name: H2:polysulfide oxidoreductase
Comments: An iron-sulfur protein. The enzyme from the hyperthermophilic archaeon Pyrococcus furiosus is part of two heterotetrameric complexes where the β and γ subunits function as sulfur reductase and the α and δ subunits function as hydrogenases (EC 1.12.1.3, hydrogen dehydrogenase [NADP+] and EC 1.12.1.4, hydrogen dehydrogenase [NAD(P)+], respectively). Sulfur can also be used as substrate, but since it is insoluble in aqueous solution and polysulfide is generated abiotically by the reaction of hydrogen sulfide and sulfur, polysulfide is believed to be the true substrate [2].
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 101637-43-8
References:
1. Zöphel, A., Kennedy, M.C., Beinert, H. and Kroneck, P.M.H. Investigations on microbial sulfur respiration. 1. Activation and reduction of elemental sulfur in several strains of Eubacteria. Arch. Microbiol. 150 (1988) 72-77.
2. Ma, K., Schicho, R.N., Kelly, R.M. and Adams, M.W. Hydrogenase of the hyperthermophile Pyrococcus furiosus is an elemental sulfur reductase or sulfhydrogenase: evidence for a sulfur-reducing hydrogenase ancestor. Proc. Natl. Acad. Sci. USA 90 (1993) 5341-5344. [PMID: 8389482]
3. Ma, K., Zhou, Z.H. and Adams, M.W. Hydrogen production from pyruvate by enzymes purified from the hyperthermophilic archaeon, Pyrococcus furiosus: A key role for NADPH. FEMS Microbiol. Lett. 122 (1994) 245-250.
4. Ma, K., Weiss, R. and Adams, M.W. Characterization of hydrogenase II from the hyperthermophilic archaeon Pyrococcus furiosus and assessment of its role in sulfur reduction. J. Bacteriol. 182 (2000) 1864-1871. [PMID: 10714990]