Molecularly imprinted polymer mimics of chymotrypsin: 1. Cooperative effects and substrate specificity

Abstract

A polymeric mimic of chymotrypsin is synthesized by grafting Co(II)-coordinated monomers-template assembly of N-methacryloyl-L -serine, N-methacryloyl-L -aspartic acid, N-methacryloyl-L -histidine and the template N-nicotinoyltyrosylbenzyl ester on crosslinked support poly(glycidylmethacrylate-co-ethylene glycol dimethacrylate). The polymeric mimic obtained after leaching out Co(II), template and ungrafted monomers was found to be hydrolytically active against substrate N-benzyloxycarbonyl-tyrosyl-para-nitrophenyl ester. The cooperative effect amongst functional groups is demonstrated by comparing the hydrolytic activity of the mimic with other polymers comprising only imidazole groups or hydroxyl and imidazole groups. Observed kinetics for hydrolysis of substrate N-benzyloxycarbonyl-tyrosyl-para-nitrophenyl ester obeyed Michaelis-Menten kinetics. The effect of molecular imprinting of the template molecule in enhancing the substrate specificity of the mimic was demonstrated. The mimic synthesized in the absence of Co(II) was found to be hydrolytically inactive.