The enzymatic synthesis of isotopically labelled penicillin Ns with isopenicillin N synthase
The preparation of isotopically labelled penicillin Ns using a chemico-enzymatic approach is described. This route involves the chemical synthesis of variously labelled D,L,D,-aminoadipoyl-cysteinyl-valine tripeptides via well established facile protocols and concludes with the conversion of these tripeptides directly into penicillin Ns by the action of recombinant isopenicillin N synthase. Milligram quantities of isotopically labelled penicillin Ns, which would otherwise represent very challenging and expensive synthetic targets, are readily accessible from this route.
Baldwin, Jack E.,Adlington, Robert M.,Crouch, Nicholas P.,Pereira, Ines A.C.
Studies on the exchange of valine-oxygen during the biosynthesis of δ-(L-α-aminoadipoyl)-L-cysteinyl-D-valine
Incorporation of [4-2H6,18O2]-valine into δ-(L-α-aminoadipoyl)-L-cysteinyl-D-valine (ACV), by intact cells of Cephalosporium acremonium, demonstrated the intracellular exchange of one and both valine oxygen atom