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EC 1.21.4.4 Details

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EC number

1.21.4.4

Accepted name

betaine reductase

Reaction

acetyl phosphate + trimethylamine + thioredoxin disulfide + H₂O = betaine + phosphate + thioredoxin

Other name(s)

acetyl-phosphate trimethylamine:thioredoxin disulfide oxidoreductase (N,N,N-trimethylglycine-forming)

Systematic name

acetyl-phosphate trimethylamine:thioredoxin disulfide oxidoreductase (betaine-forming)

CAS registry number

125752-87-6

Comment

The reaction is observed only in the direction of betaine reduction. The enzyme from Eubacterium acidaminophilum consists of subunits A, B and C. Subunit B contains selenocysteine and a pyruvoyl group, and is responsible for betaine binding and trimethylamine release. Subunit A, which also contains selenocysteine, is reduced by thioredoxin, and is needed to convert the carboxymethyl group into a ketene equivalent, in turn used by subunit C to produce acetyl phosphate. Only subunit B distinguishes this enzyme from EC 1.21.4.2 (glycine reductase) and EC 1.21.4.3 (sarcosine reductase).

History

created 2003, modified 2010

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

1.13 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

1.21.4.1 D-proline reductase

1.21.4.2 glycine reductase

1.21.4.3 sarcosine reductase

1.21.4.4 betaine reductase

1.21.4.5 tetrachlorohydroquinone reductive dehalogenase

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)