Synthesis of δ-(α-aminoadipyl)cysteinylvaline and its role in penicillin biosynthesis

Abstract

The stereoisomers of .delta.-(.alpha.-aminoadipyl)-L-cysteinylvaline (LLD, LLL and DLD) were synthesized from valine labeled with 3H in its methyl groups or in the .alpha. position. L-Cysteinyl-D-[4,4''-3H]valine was also synthesized. 3H was incorporated into a compound that behaved like penicillin N when the LLD tripeptide containing either a methyl- or an .alpha.-labeled valine residue was incubated with a cell-free system prepared by lysis of protoplasts of Cephalosporium acremonium. Incorporation was not observed under these conditions from the labeled all-L- or DLD-tripeptide, from L-cysteinyl-D-[4,4''-3H]valine, or from DL-[4,4''-3H]valine. .delta.-(.alpha.-Aminoadipyl)cysteinylvaline extracted from the mycelium of Penicillium chrysogenum may be the LLD isomer, like that from C. acremonium.