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EC 1.12.98.4 Details

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EC number

1.12.98.4

Accepted name

sulfhydrogenase

Reaction

H₂ + (sulfide)_n = hydrogen sulfide + (sulfide)_n-1

Other name(s)

sulfur reductase

Systematic name

H₂:polysulfide oxidoreductase

Comment

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].

History

created 1992 as EC 1.97.1.3, transferred 2013 to EC 1.12.98.4

EC Tree

1 Oxidoreductases

1.1 Acting on the CH-OH group of donors

1.2 Acting on the aldehyde or oxo group of donors

1.3 Acting on the CH-CH group of donors

1.4 Acting on the CH-NH₂ group of donors

1.5 Acting on the CH-NH group of donors

1.6 Acting on NADH or NADPH

1.7 Acting on other nitrogenous compounds as donors

1.8 Acting on a sulfur group of donors

1.9 Acting on a heme group of donors

1.10 Acting on diphenols and related substances as donors

1.11 Acting on a peroxide as acceptor

1.12 Acting on hydrogen as donor

1.12.1 With NAD⁺ or NADP⁺ as acceptor

1.12.2 With a cytochrome as acceptor

1.12.5 With a quinone or similar compound as acceptor

1.12.7 With an iron-sulfur protein as acceptor

1.12.98 With other, known, physiological acceptors

1.12.98.1 coenzyme F₄₂₀ hydrogenase

1.12.98.2 5,10-methenyltetrahydromethanopterin hydrogenase

1.12.98.3 Methanosarcina-phenazine hydrogenase

1.12.98.4 sulfhydrogenase

1.12.99 With unknown physiological acceptors

1.13 Acting on single donors with incorporation of molecular oxygen (oxygenases)

1.14 Acting on paired donors, with incorporation or reduction of molecular oxygen

1.15 Acting on superoxide as acceptor

1.16 Oxidizing metal ions

1.16.1 With NAD⁺ or NADP⁺ as acceptor

1.16.3 With oxygen as acceptor

1.16.5 With a quinone or similar compound as acceptor

1.16.8 With a flavin as acceptor

1.16.9 With a copper protein as acceptor

1.16.98 With other, known, physiological acceptors

1.16.99 With unknown physiological acceptors

1.17 Acting on CH or CH₂ groups

1.17.1 With NAD⁺ or NADP⁺ as acceptor

1.17.2 With a cytochrome as acceptor

1.17.3 With oxygen as acceptor

1.17.4 With a disulfide as acceptor

1.17.5 With a quinone or similar compound as acceptor

1.17.7 With an iron-sulfur protein as acceptor

1.17.8 With a flavin as acceptor

1.17.9 With a copper protein as acceptor

1.17.98 With other, known, physiological acceptors

1.17.99 With unknown physiological acceptors

1.18 Acting on iron-sulfur proteins as donors

1.19 Acting on reduced flavodoxin as donor

1.20 Acting on phosphorus or arsenic in donors

1.21 Catalysing the reaction X-H + Y-H = X-Y

1.22 Acting on halogen in donors

1.23 Reducing C-O-C group as acceptor

1.97 Other oxidoreductases

1.98 Enzymes using H₂ as reductant (deleted subclass)

1.99 Other enzymes using O₂ as oxidant (deleted subclass)