Amino-acid racemase able to utilize a broad range of substrates. Is mostly active with lysine and arginine and, to a lesser extent, with ornithine, whereas is about 10 times less active with alanine, methionine and ethionine. With phenylalanine as substrate only a trace activity is detectable, and is inactive with glutamate. Plays a key role in the catabolism of D-arginine and D-lysine, that allows P.taetrolens strain NBRC 3460 to grow on these basic D-amino acids as a sole carbon source. an L-alpha-amino acid = a D-alpha-amino acid L-lysine = D-lysine L-arginine = D-arginine L-ornithine = D-ornithine L-alanine = D-alanine L-methionine = D-methionine kcat is 109.0 sec(-1) with L-lysine as substrate. kcat is 104.0 sec(-1) with D-lysine as substrate. kcat is 119.0 sec(-1) with L-arginine as substrate. kcat is 119.0 sec(-1) with D-arginine as substrate. kcat is 87.7 sec(-1) with L-ornithine as substrate. kcat is 87.3 sec(-1) with D-ornithine as substrate. kcat is 2.4 sec(-1) with L-alanine as substrate. kcat is 2.6 sec(-1) with D-alanine as substrate. Optimum pH is 8.0. Optimum temperature is 65 degrees Celsius. Homodimer. Is translocated into the periplasm via a Tat-independent protein translocation pathway and, therefore, must have been translocated via the Sec route. Cells lacking this gene are no longer able to utilize D-Lys as a sole carbon source for growth, and also the utilization of D-Arg is strongly reduced. The growth of the deletion mutant strain on LB medium is slightly retarded as compared to the wild type, which might indicate that ArgR is also generally involved in amino acid degradation. Belongs to the alanine racemase family. Bsr subfamily.