Reaction: acetyl phosphate + NH3 + thioredoxin disulfide + H2O = glycine + phosphate + thioredoxin
For diagram click here.
Systematic name: acetyl-phosphate ammonia:thioredoxin disulfide oxidoreductase (glycine-forming)
Comments: The reaction is observed only in the direction of glycine 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 glycine binding and ammonia 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 1.21.4.3 (sarcosine reductase) and EC 1.21.4.4 (betaine reductase).
Links to other databases: BRENDA, EXPASY, KEGG, Metacyc, CAS registry number: 254889-62-8
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. [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]