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. Incubation of phenoxyacetyl-L-cysteinyl-D-valine (PoCV) under the same reaction conditions did not result in the formation of penicillin V or any cephalosporin product.