Synthesis of isopenicillin derivatives in the absence of living cells

Abstract

Isopenicillin derivatives having antimicrobial properties and a general formula of: ##STR1## where R, R.sub.1, and R.sub.2 are hydrogen, methyl, ethyl, propyl, isopropyl, or halogenated methyl, ethyl, propyl or isopropyl radicals and R.sub.3 is ##STR2## are produced in a cell-free system using an extract from Cephalosporium acremonium. The starting materials for the synthesis consist of tripeptides composed of unsubstituted or .beta.-substituted D-valine, unsubstituted or substituted L cysteine, and L- .alpha.-aminoadipic acid or its analogues. Certain enzymes in the cell-free extract are inactivated so that conversion does not proceed past the isopenicillin stage.

Dependencies are inferred from the claim text.