The Effect of a Water Molecule on the Mechanism of Formation of Compound 0 in Horseradish Peroxidase

• DOI: 10.1021/ja0676861
• Publication Date: 2007-05-02T15:15:56Z
• Authors: Etienne Derat; Sason Shaik; Carme Rovira; Pietro Vidossich; Mercedes Alfonso-...
• Keywords: Horseradish peroxidase; Catalytic cycle; Acceptor

We demonstrate by QM/MM calculations that the formation of Compound 0, an intermediate in catalytic cycle horseradish peroxidase, is catalyzed a single water molecule, which relays proton transfer between substrate (H2O2) and acceptor (His42). Thus, molecule enhances thermodynamic kinetic acidities H2O2 many orders magnitude. The behavior during activation may account for experimental reports extensive entropic effects principal active species enzyme I.