Purification and Some Properties of Taurine Dehydrogenase from a Bacterium

Abstract

Taurine dehydrogenase was solubilized and purified 13-fold from a taurine-decomposing bacterium by ammonium sulfate precipitation and Sepharose 4B gel filtration. The partially purified enzyme did not catalyze the oxidation of taurine by oxygen directly, but did do so in the presence of phenazine methosulfate. The optimal pH was 8.4. Fifty percent of the enzyme activity was lost on incubation at 40°C for 20 min. The K_m values of the enzyme for taurine and phenazine methosulfate were determined to be 2×10⁻²M and 5.6×10⁻⁵M, respectively. Taurine was the only substrate oxidized among a variety of amines. Nicotinamide nucleotides and flavin nucleotides did not serve as electron acceptors. The enzyme reaction was inhibited by isonicotinic acid 2-isopropylhydrazide, phenelzine, and p-chloromercuribenzoate. The reaction product was identified by paper chromatography and electrophoresis as sulfoacetaldehyde, and ammonia formation and oxygen consumption occurred stoichiometrically.