Enzyme-like Synthetic Catalysts (Synzymes)

Abstract

Publisher Summary This chapter illustrates many of the basic elements of enzyme catalysis, including binding of substrate, multifunctional catalysis, microenvironmental effects, covalent catalysis, and strain effects. The most remarkable rate enhancements are those brought about by apolar derivatives of polyethyleneimine (PEI), a polycation. These rate enhancements are very encouraging in that they are most likely produced by strong binding and microenvironmental effects. The structure of apolar PEI derivatives has been probed using fluorescence spectroscopy and 19F-NMR. The results indicates that the apolar groups of PEI cluster to form a hydrophobic pool in the interior of the molecule. This area is accessible to water, however. One could picture substrates being bound in the pool, and migrating until a catalytic group is encountered. If this model is correct, the very large rate enhancements brought about by PEI are probably not a result of highly precise alignment of catalytic groups with the substrate molecule. Strain effects would also seem unlikely.