Je. Baldwin et al., The enzymatic synthesis of isotopically labelled penicillin Ns with isopenicillin N synthase, J LABEL C R, 41(12), 1998, pp. 1145-1163
The preparation of isotopically labelled penicilllin Ns using a chemico-enz
ymatic approach is described. This route involves the chemical synthesis of
variously labelled (D) under bar,(L) under bar,(D) under bar,-aminoadipoyl
-cysteinyl-valine tripeptides via well established facile protocols and con
cludes with the conversion of these tripeptides directly into penicillin Ns
by the action of recombinant isopenicillin N synthase. Milligram quantitie
s of isotopically labelled penicillin Ns, which would otherwise represent v
ery challenging and expensive synthetic targets, are readily accessible fro
m this route.