ID 1.21.4.4 DE betaine reductase. CA [thioredoxin]-disulfide + acetyl phosphate + H2O + trimethylamine = CA [thioredoxin]-dithiol + glycine betaine + H(+) + phosphate. CC -!- The reaction is observed only in the direction of betaine reduction. CC -!- The enzyme from Eubacterium acidaminophilum consists of subunits A, CC B and C. CC -!- Subunit B contains selenocysteine and a pyruvoyl group, and is CC responsible for glycine binding and ammonia release. CC -!- Subunit A, which also contains selenocysteine, is reduced by CC thioredoxin, and is needed to convert the carboxymethyl group into a CC ketene equivalent, in turn used by subunit C to produce acetyl CC phosphate. CC -!- Only subunit B distinguishes this enzyme from EC 1.21.4.2 and CC EC 1.21.4.3. DR P50972, GRDA1_PEPAC; Q6LH20, GRDA1_PHOPR; O32518, GRDA2_PEPAC; DR Q6LH19, GRDA2_PHOPR; P26971, GRDA_ACESD ; A6TU46, GRDA_ALKMQ ; DR Q3A9J5, GRDA_CARHZ ; A7FTE0, GRDA_CLOB1 ; A7GCV1, GRDA_CLOBL ; DR P26970, GRDA_GOTPU ; P52216, GRDA_PEPLI ; Q67KE6, GRDA_SYMTH ; DR Q73PQ2, GRDA_TREDE ; P54935, GRDC_PEPAC ; Q47878, GRDD_PEPAC ; DR O69407, GRDH_PEPAC ; O69406, GRDI_PEPAC ; //