| EC |
1.21.4.4 |
| Accepted name: |
betaine reductase |
| Reaction: |
acetyl phosphate + trimethylamine + thioredoxin disulfide + H2O = betaine + phosphate + thioredoxin |
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For diagram of possible mechanism, click here |
| Glossary: |
betaine = glycine betaine = N,N,N-trimethylglycine = N,N,N-trimethylammonioacetate |
| 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 1.21.4.2 (glycine reductase) and EC 1.21.4.3 (sarcosine reductase). |
| Links to other databases: |
BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number: 125752-87-6 |
| References: |
| 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. [DOI] [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. [DOI] [PMID: 11422384] |
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| [EC 1.21.4.4 created 2003, modified 2010] |
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