Quantum-chemical insights into mechanisms of the nonenzymatic hydrolysis of phosphate monoesters

The interpretation of a large number of experiments that are generally cons idered to support the dissociative or metaphosphate mechanism of phosphate monoesters in aqueous solution is scrutinized using results of ab initio qu antum chemical calculations. It is concluded that while it is currently not clear whether the associative or dissociative mechanism of phosphate monoe ster hydrolysis is operating in aqueous solution, the associative transitio n state can be better stabilized by the interaction between the equatorial oxygens and the proton donor groups in the enzyme active sites.