PURIFICATION AND CHARACTERIZATION OF L-AMINOACYLASE FROM PSEUDOMONAS-MALTOPHILA B1

The constitutive L-aminoacylase, which is used for optical resolution of DL-alpha-aminosuberic add (DL-Asu), has been purified and character ized from Pseudomonas maltophila B1. The crude enzyme showed a specifi c activity of 0.062 units/mg for N-acetyl(Ac)-L-Asu. This value is ver y high compared with those from Aspergillus melleus, porcine kidney, a nd Bacillus stearothermophilus. Molecular masses of 108 kDa for the na tive enzyme and 50 kDa for the subunit were determined, indicating a d imer. The enzyme activity was optimal at pH 8.0 and at 55 degrees C. T he enzyme hydrolyzed N-acyl derivatives of various neutral L-amino aci ds and acidic L-amino acids, L-glutamate and L-Asu. The enzyme also ha d dipeptidase activity. The K-m values for N-Ac-L-alanine and N-Ac-DL- Asu were determined at 2.32 and 12.7 mM, respectively. The apoenzyme w as activated using Zn2+, Ca2+, and Co2+. Glyoxylate, DL-lactate, pheny lboronic acid (PBA), butaneboronic acid (BBA), diethylpyrocarbonate (D EP), and phenylglyoxal (PGO) inhibited enzyme activity.