Synthesis of benzylpenicillin by cell-free extracts from Streptomyces clavuligerus.

Cell-free enzyme concentrates from Streptomyces clavuligerus were found to convert phenylacetyl-L-cysteinyl-D-valine (PCV) directly into benzylpenicillin when incubated under reaction conditions which support the activity of isopenicillin N synthetase. The formation of benzylpenicillin was detected both by biological assay and by high performance liquid chromatography. Supplementation of PCV-containing reaction mixtures with cofactors required for ring expansion activity did not result in the production of cephalosporins.

Enzymatic synthesis of the penicillin and cephalosporin nuclei from an acyclic peptide containing carboxymethylcysteine.

The tripeptide delta-(L- carboxymethylcysteinyl )-L-cysteinyl-D-valine (L-CMC-CV) is converted sequentially into the CMC analog of isopenicillin N, the CMC analog of penicillin N, and the CMC analog of desacetoxycephalosporin C by, respectively, isopenicillin N synthetase, isopenicillin N epimerase, and desacetoxycephalosporin C synthetase, all isolated from the beta-lactam producing prokaryote Streptomyces clavuligerus.