Geometrical effect of 3D-memory cavity on the imprinting efficiency of transition-state analogue-built artificial hydrolases

Abstract

Highlighting biomimetic recognition and shape-selective binding, highly crosslinked transition-state analogue-imprinted artificial hydrolases are synthesized from amino acid monomers. Two different transition-state analogues—TSAs—are used for the preparation of the enzyme mimic polymer catalysts. The catalytic hydrolysis of amino acid p-nitroanilides is found to be dependent on the geometry of the TSA imprints on the polymer matrix. The imprinted TSA facilitates tetrahedral complementarity to the transition-state intermediate of hydrolysis. The geometry of the 3D-memory cavity fabricated by the print molecule along with the catalytic entities is accountable for the higher catalytic competence of the imprinted enzyme mimics over the non-imprinted control polymers. The super crosslinked macroporous polymer matrix, in which the catalytic functions are suitably oriented in a ‘3D pocket’ for selective binding of the substrate through H-bonding, is accountable for the high imprinting efficiency of the imprinted polymer catalysts. The imprinted mimics are found to be exhibiting cross-selectivity in their catalytic properties. Even though the mimics could not compete with native enzyme, they exhibit higher thermal stability, increased shelf-life and superior reusability.