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EC 1.8.98.4 Details

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EC number

1.8.98.4

Accepted name

coenzyme F₄₂₀:CoB-CoM heterodisulfide,ferredoxin reductase

Reaction

2 oxidized coenzyme F₄₂₀ + 2 reduced ferredoxin [iron-sulfur] cluster + CoB + CoM + 2 H⁺ = 2 reduced coenzyme F₄₂₀ + 2 oxidized ferredoxin [iron-sulfur] cluster + CoM-S-S-CoB

Other name(s)

hdrA2B2C2 (gene names)

Systematic name

CoB,CoM,ferredoxin:coenzyme F₄₂₀ oxidoreductase

Comment

The enzyme, characterized from the archaeon Methanosarcina acetivorans, catalyses the reduction of CoB-CoM heterodisulfide back to CoB and CoM. The enzyme consists of three components, HdrA, HdrB and HdrC, all of which contain [4Fe-4S] clusters. Electrons enter at HdrA, which also contains FAD, and are transferred via HdrC to the catalytic component, HdrB. During methanogenesis from acetate the enzyme catalyses the activity of EC 1.8.7.3, ferredoxin:CoB-CoM heterodisulfide reductase. However, it can also use electron bifurcation to direct electron pairs from reduced coenzyme F₄₂₀ towards the reduction of both ferredoxin and CoB-CoM heterodisulfide. This activity is proposed to take place during Fe(III)-dependent anaerobic methane oxidation. cf. EC 1.8.98.5, H₂:CoB-CoM heterodisulfide,ferredoxin reductase, EC 1.8.98.6, formate:CoB-CoM heterodisulfide,ferredoxin reductase, and EC 1.8.98.1, dihydromethanophenazine:CoB-CoM heterodisulfide reductase.

History

created 2017

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

1.8.1 With NAD⁺ or NADP⁺ as acceptor

1.8.2 With a cytochrome as acceptor

1.8.3 With oxygen as acceptor

1.8.4 With a disulfide as acceptor

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

1.8.98.1 dihydromethanophenazine:CoB-CoM heterodisulfide reductase

1.8.98.2 sulfiredoxin

1.8.98.3 sulfite reductase (coenzyme F₄₂₀)

1.8.98.4 coenzyme F₄₂₀:CoB-CoM heterodisulfide,ferredoxin reductase

1.8.98.5 H₂:CoB-CoM heterodisulfide,ferredoxin reductase

1.8.98.6 formate:CoB-CoM heterodisulfide,ferredoxin reductase

1.8.98.7 cysteine-type anaerobic sulfatase-maturating enzyme

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

1.12.1 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

1.12.99 With unknown physiological acceptors

1.12.99.1 created 1989, deleted 2002

1.12.99.2 created 1992, deleted 2002

1.12.99.3 created 1999, deleted 2002

1.12.99.4 created 1999, deleted 2002

1.12.99.5 created 1999, deleted 2001

1.12.99.6 hydrogenase (acceptor)

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

1.97.1 Sole sub-subclass for oxidoreductases that do not belong in the other subclasses

1.98 Enzymes using H₂ as reductant (deleted subclass)

1.99 Other enzymes using O₂ as oxidant (deleted subclass)