Laue H, Smits TH, Schumacher UK, Claros MC, Hartemink R, Cook AM.

FEMS Microbiol Lett. 2006 Aug;261(1):74-9.

PMID: 16842362

Bilophila wadsworthia RZATAU is a Gram-negative bacterium which converts the sulfonate taurine (2-amino- ethanesulfonate) to ammonia, acetate and sulfide in an anaerobic respiration. Taurine:pyruvate aminotransferase (Tpa) catalyses the initial metabolic reaction yielding alanine and sulfoacetaldehyde. We purified Tpa 72-fold to apparent homogeneity with an overall yield of 89%. The purified enzyme did not require addition of pyridoxal 5H-phosphate, but highly active enzyme was only obtained by addition of pyridoxal 5H-phosphate to all buffers during purification. SDS/PAGE revealed a single protein band with a molecular mass of 51 kDa. The apparent molecular mass of the native enzyme was 197 kDa as determined by gel filtration, which indicates a homotetrameric structure. The kinetic constants for taurine were: Km 7.1 mm, Vmax 1.20 nmol ́sP1, and for pyruvate: Km 0.82 mm, Vmax 0.17 nmol ́sP1. The purified enzyme was able to transaminate hypotaurine (2-aminosulfinate), taurine, b-alanine and with low activity cysteine and 3-aminopropanesulfonate. In addition to pyruvate, 2-ketobutyrate and oxaloacetate were utilized as amino group acceptors. We have sequenced the encoding gene (tpa). It encoded a 50-kDa peptide, which revealed 33% identity to diaminopelargonate aminotransferase from Bacillus subtilis