A dinuclear macrocylcic amine ligand with a proximal cyclodextrin ring was synthesized for demonstrating cooperative hydrolysis of an activated ester mimicking the active site of carboxypeptidase A. The macrocyclic polyamine presented a tetrahedral coordination site for the catalytic Zn(II) ions whereas a proximal β-cyclodextrin moiety afforded binding site for alkaline earth metal ions. This presentation will focus on the synthesis of the enzyme mimic as well as its effectiveness to catalyze the hydrolysis of an activated ester at the pH corresponding to the pKa of the Zn(II) bound water that upon deprotonation serves as a nucleophile during the hydrolysis. Rate enhancements of the Zn(II) complex in presence of Mg(II), Ca(II), Ba(II) and Sr(II) ions bound to β-cyclodextrin over those of the complex in the absence of the alkaline earth metal ions will be presented to demonstrate their cooperative effect on substrate hydrolysis.

Catalytic activity and nucleophilicity of a hydrolytic metalloenzyme mimic

255th National Meeting (2018)

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