Catalyzes the interconversion of L-alanine and D-alanine, and L-serine and D-serine. Has weak activity with valine and threonine. L-alanine = D-alanine L-serine = D-serine Completely inhibited by hydroxylamine hydrochloride. Optimum pH is 6.5-7.0. Highly stable at high temperatures. Homohexamer. Belongs to the class-III pyridoxal-phosphate-dependent aminotransferase family.