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 k_cat/k_uncat . The efficiency k_cat/K_m 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.