Involved in the degradation of beta-alanine. Catalyzes the transfer of the amino group from beta-alanine to pyruvate to yield L-alanine and 3-oxopropanoate. It can also accept both 4-aminobutyrate and (S)-alpha-methylbenzylamine (MBA) as amino-group donors in the presence of pyruvate as an amine acceptor. 3-oxopropanoate + L-alanine = beta-alanine + pyruvate Inhibited by gabaculine (5-amino-1,3-cyclohexadienylcarboxylic acid). Homotetramer. Activated by BauR. Cells lacking this gene grow normally on putrescine, cadaverine, and GABA, but growth on beta-alanine is completely abolished. Belongs to the class-III pyridoxal-phosphate-dependent aminotransferase family.