Purification and Characterization of Arginine Amidinohydrolase from Bacillus brevis TT02-8

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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 p^I 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 K_ms for L-arginine and L-canavanine were 0. 69 and 22. 2 mM, respectively. The enzyme was inhibited competitively by γ-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.