IUBMB Enzyme Nomenclature


Accepted name: betaine reductase

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

For diagram of reaction click here.

Glossary: betaine = glycine betaine = N,N,N-trimethylglycine

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

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

Comments: 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 (glycine reductase) and EC (sarcosine reductase).

Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 125752-87-6


1. Wagner, M., Sonntag, D., Grimm, R., Pich, A. Eckerskorn, C., Söhling, B. and Andreesen, J.R. Substrate-specific selenoprotein B of glycine reductase from Eubacterium acidaminophilum. Eur. J. Biochem. 260 (1999) 38-49. [PMID: 10091582]

2. Bednarski, B., Andreesen, J.R. and Pich, A. In vitro processing of the proproteins GrdE of protein B of glycine reductase and PrdA of D-proline reductase from Clostridium sticklandii: formation of a pyruvoyl group from a cysteine residue. Eur. J. Biochem. 268 (2001) 3538-3544. [PMID: 11422384]

[EC created 2003]

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