Functional mimicry of the active site of carboxypeptidase a by a molecular imprinting strategy: cooperativity of an amidinium and a copper ion in a transition-state imprinted cavity giving rise to high catalytic activity.

Abstract

A model for the natural enzyme carboxypeptidase A was prepared by molecular imprinting in synthetic polymers. An unusually high activity and efficiency for carbonate hydrolysis could be obtained by imprinting with a stable transition-state analogue template and introducing an amidinium group and a Cu2+ ion-binding site in a defined orientation to each other into the active site. With substrates having a very similar structure to the template, extraordinarily high enhancements of rates of 110 000-fold were obtained of catalyzed to uncatalyzed reaction kcat/kuncat . The efficiency kcat/Km of the molecularly imprinted catalysts compared to that of the nonimprinted control polymers containing the same functional groups was 790-fold higher, a clear indication of a very efficient imprinting procedure.