Isomerizes L-alanine to D-alanine which is then likely oxidized to pyruvate by DadA. Shows racemase activity with both alanine stereoisomers, negligible activity with D-cysteine and L-serine, and exhibits no activity with the remaining natural chiral amino acids. L-alanine = D-alanine kcat is 37.47 sec(-1) with D-alanine as substrate. kcat is 92.0 sec(-1) with L-alanine as substrate. Amino-acid biosynthesis; D-alanine biosynthesis; D-alanine from L-alanine: step 1/1. Belongs to the alanine racemase family.