Quantum Chemical Studies for the Mechanism of Phosphate Monoester Hydrolysis

Abstract

Hydrolysis of phosphate containing compounds is important chemical reaction involved in many life processes such as DNA scission, cell division and organelle movement. Density functional theory calculations at M06-2X/6-31+G* and B3LYP/6-31+G** level of theory were carried out to calculate the mechanism of hydrolysis of phosphate monoester. For these calculations, two different starting set-ups of phosphate monoester, each differing with respect to the number of water molecules, were chosen. The stationary points along the potential energy surface that connect the reactant and the product structure were identified. The findings show that the energy barrier of the uncatalyzed hydrolysis of phosphate monoester in gas-phase is in the range of 37 to 48 kcal mol-1 . The mechanism of hydrolysis involves only a single water molecule. The stationary points along the minimum energy pathway of phosphate monoester hydrolysis involve the characteristics of both sequential (dissociative) as well as concurrent (associative) mechanisms. Adding explicit water molecule or the incorporation of implicit solvation model lower the energy barrier of hydrolysis.