Purification and characterization of arginine amidinohydrolase from Bacillus brevis TT02-8

A bacterial arginase was purified to homogeneity from a strain of Bacillus brevis. The native enzyme, with an estimated MW of 143,000, migrated on SDS-PAGE as a single polypeptide of estimated MW of 33,000. The enzyme, highly specific to L-arginine, showed the maximum activity at pH 11.0 in the presence of Mn2+ ions and the pI was 4.8 by isoelectric focusing. The enzyme activity was increased significantly by the addition of Mn2+, Ni2+, or Co2+ ions, and inhibited potently by chemicals such as HgCl2, N-bromosuccinimide, or glutathione. The Kms for L-arginine and L-canavanine were 0.69 and 22.2 mM, respectively. The enzyme was inhibited competitively by gamma-guanidinobutyric acid, and non-competitively by L-lysine, L-ornithine, creatine, blasticidin S, and edeine B1. Analysis of the N-terminal amino acid sequence of the purified bacterial enzyme found 33-36% homologies with the Agrobacterium, yeast, rat, and human enzymes.