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EC 1.8.1.2 Details

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EC number

1.8.1.2

Accepted name

assimilatory sulfite reductase (NADPH)

Reaction

hydrogen sulfide + 3 NADP⁺ + 3 H₂O = sulfite + 3 NADPH + 3 H⁺

Other name(s)

sulfite reductase (NADPH), sulfite (reduced nicotinamide adenine dinucleotide phosphate) reductase, NADPH-sulfite reductase, NADPH-dependent sulfite reductase, H₂S-NADP oxidoreductase, sulfite reductase (NADPH₂), MET5 (gene name), MET10 (gene name), cysI (gene name), cysJ (gene name)

Systematic name

hydrogen-sulfide:NADP⁺ oxidoreductase

CAS registry number

9029-35-0

Comment

Contains siroheme, [4Fe-4S] cluster, FAD and FMN. The enzyme, which catalyses the six-electron reduction of sulfite to sulfide, is involved in sulfate assimilation in bacteria and yeast. Different from EC 1.8.99.5, dissimilatory sulfite reductase, which is involved in prokaryotic sulfur-based energy metabolism. cf. EC 1.8.7.1, assimilatory sulfite reductase (ferredoxin).

History

created 1961, modified 2015

EC Tree

1 Oxidoreductases

1.1 Acting on the CH-OH group of donors

1.1.1 With NAD⁺ or NADP⁺ as acceptor

1.1.2 With a cytochrome as acceptor

1.1.3 With oxygen as acceptor

1.1.4 With a disulfide as acceptor

1.1.5 With a quinone or similar compound as acceptor

1.1.7 With an iron-sulfur protein as acceptor

1.1.9 With a copper protein as acceptor

1.1.98 With other, known, physiological acceptors

1.1.99 With unknown physiological acceptors

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

1.8.1 With NAD⁺ or NADP⁺ as acceptor

1.8.2 With a cytochrome as acceptor

1.8.2.1 sulfite dehydrogenase (cytochrome)

1.8.2.2 thiosulfate dehydrogenase

1.8.2.3 sulfide-cytochrome-c reductase (flavocytochrome c)

1.8.2.4 dimethyl sulfide:cytochrome c₂ reductase

1.8.2.5 thiosulfate reductase (cytochrome)

1.8.2.6 S-disulfanyl-L-cysteine oxidoreductase

1.8.2.7 thiocyanate desulfurase

1.8.3 With oxygen as acceptor

1.8.4 With a disulfide as acceptor

1.8.4.1 glutathione—homocystine transhydrogenase

1.8.4.2 protein-disulfide reductase (glutathione)

1.8.4.3 glutathione—CoA-glutathione transhydrogenase

1.8.4.4 glutathione—cystine transhydrogenase

1.8.4.5 methionine-S-oxide reductase

1.8.4.6 protein-methionine-S-oxide reductase

1.8.4.7 enzyme-thiol transhydrogenase (glutathione-disulfide)

1.8.4.8 phosphoadenylyl-sulfate reductase (thioredoxin)

1.8.4.9 adenylyl-sulfate reductase (glutathione)

1.8.4.10 adenylyl-sulfate reductase (thioredoxin)

1.8.4.11 peptide-methionine (S)-S-oxide reductase

1.8.4.12 peptide-methionine (R)-S-oxide reductase

1.8.4.13 L-methionine (S)-S-oxide reductase

1.8.4.14 L-methionine (R)-S-oxide reductase

1.8.4.15 protein dithiol oxidoreductase (disulfide-forming)

1.8.4.16 thioredoxin:protein disulfide reductase

1.8.5 With a quinone or similar compound as acceptor

1.8.6 With a nitrogenous group as acceptor (deleted sub-subclass)

1.8.7 With an iron-sulfur protein as acceptor

1.8.98 With other, known, physiological acceptors

1.8.99 With unknown physiological acceptors

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

1.13 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

1.17 Acting on CH or CH₂ groups

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

1.21.1 With NAD⁺ or NADP⁺ as acceptor

1.21.3 With oxygen as acceptor

1.21.4 With a disulfide as acceptor

1.21.98 With other, known, physiological acceptors

1.21.99 With unknown physiological acceptors

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)