THEORETICAL CALCULATIONS OF HYDROLYSIS ENERGIES OF SOME HIGH-ENERGY MOLECULES .2. SURVEY OF SOME BIOLOGICALLY IMPORTANT HYDROLYTIC REACTIONS

We present ab initio calculations on most of the major classes of hydrolytic reactions of high-energy molecules of importance in biological processes. Although intramolecular (opposing resonance and electrostatic) effects play an important role in determining the energy of hydrolysis in some of these reactions, it is concluded that in those hydrolyses of most importance in energy storage and transduction (ATP→ADP+orthophosphate and phosphocreatine+ADP creatine+ATP), relative solvation energies of reactants and products are by far the most important factors in determining these energies. We applied simple reaction field equations to estimate solvation energies. By doing so, we are able to reproduce the fact that phos-phoguanidinium and pyrophosphate ions have similar free energies of hydrolysis in H2O. despite the huge calculated difference between the corresponding energies of hydrolysis in the gas phase. © 1978, American Chemical Society. All rights reserved.