Amino-acid racemase that catalyzes the interconversion of L-lysine and D-lysine, and L-arginine and D-arginine (PubMed:23118975). To a lesser extent, is also able to interconvert alanine and isoleucine enantiomers (PubMed:23118975, PubMed:22806802). an L-alpha-amino acid = a D-alpha-amino acid L-lysine = D-lysine L-arginine = D-arginine L-alanine = D-alanine Activity is enhanced by Co(2+), Mn(2+) and Sr(2+), and decreased by Cu(2+). kcat is 4238 min(-1) with L-alanine as substrate (PubMed:22806802). kcat is 3545 min(-1) with L-lysine as substrate. kcat is 2228 min(-1) with L-arginine as substrate (PubMed:23118975). Optimum pH is 9.0. Optimum temperature is 37 degrees Celsius. Monomer (PubMed:22806802). Forms a head-to-tail homodimer in the structure (PubMed:23118975). The active-site cleft is located at the dimeric interface and contains the two conserved catalytic residues, a lysine from one subunit and a tyrosine from the other subunit. Belongs to the alanine racemase family. Bsr subfamily.