Theoretical study of hydrolytic deamination by adenosine deaminase and the role of zn in the catalytic process

Abstract

The present work was designed to gain an insight into the enzymatic catalysis performed by a specific group of enzymes, Zn-metalloenzymes. A detailed review of the literature yielded five enzymes participating in the hydrolytic bond breaking reactions which were of interest for the theoretical study of Zn metalloenzymes. For these enzymes the common reaction step, activation of water by deprotonation of a Zn-bound water ligand, was identified from literature review. The water activation was studied in detail for the five different enzymes and it was found that the process is facilitated by a combined effect of water polarization by Zn, and the stabilizing effect that the Zn coordination center has on the resulting hydroxide. The present work also explored in detail the reaction mechanism of one particular enzyme, adenosine deaminase. A novel and complete description of the reaction mechanism for this enzyme was achieved, providing with important new insights into the details of hydrolytic reactions which would not be available from experimental work.