Deacetylation of PS-5, a new beta-lactam compound. III. Enzymological characterization of L-amino acid acylase and D-amino acid acylase from Pseudomonas sp. 1158

Abstract

L-Amino acid acylase and D-amino acid acylase were stable below 50 degrees C, although the D-enzyme was more thermostable than the L-enzyme at higher temperatures. At 30 degrees C they showed the highest reaction velocity in phosphate buffer of pH 7.4. Hg++ and Cu++ severely inactivated their activity. Activation by Co++ was observed on L-amino acid acylase, but not on D-amino acid acylase. p-Chloromercuribenzoate inhibited both enzymes, whereas ethylenediamine tetraacetate was very inhibitory on L-amino acid acylase only. With N-acetyl- and N-chloroacetyl-amino acids as substrates, they were relatively stereo-specific. They acted as a peptidase on dipeptides and tripeptides. Although N-acetylglycine was attacked by the two enzymes, N-acetylglucosamine and N-acetylethanolamine were insusceptible. PS-5 was converted to NS-5 (deacetyl PS-5) by L-amino acid acylase as well as by D-amino acid acylase.