Studies on the biosynthesis of carbapenem antibiotics. III. Enzymological characterization of the L-amino acid acylase activity of A933 acylase.

A933 acylase, which is involved in exchange of the pantothenyl substituent of OA-6129 carbapenems with acetyl CoA, was characterized as an L-amino acid acylase with a molecular weight of 100,000 (+/- 8,000) and a pI value of 5.1. The highest L-amino acid acylase activity of A933 acylase was observed at 37 degrees C and pH 7 approximately 7.5 for N-chloroacetyl-L-phenylalanine. Unlike other amino acid acylases, A933 acylase was severely inhibited by cobalt ions and p-chloromercuribenzoate. The acylase also showed peptidase activity with some di- and tripeptides. A protein fraction with A933 L-amino acid acylase activity from blocked mutant 1501 lacked OA-6129A-depantothenylating activity.