title: Proton assisted oxygen-oxygen bond splitting in cytochrome p450.
abstract: Proton assisted O-O bond splitting of cytochromes' P450 hydroperoxo Compound 0 has been investigated by density functional theory, showing a barrier for the slightly endothermic formation of the iron-oxo Compound I. The barrier and the endothermicity increase with decreasing acidity of the distal proton source. Protonation of the proximal iron heme ligand favors the O-O bond scission and provides an important regulatory component in the catalytic cycle. The Compound 0 --> I conversion is slightly exothermic for the peroxidase and catalase models. Implications of the energetic relationship between the two reactive intermediates are discussed in terms of possible oxidative pathways.
authors: Vrije Universiteit, FEW, Department of Chemistry, De Boelelaan 1083, 1081 HV Amsterdam, The Netherlands.
authors: André R
authors: AR
authors: Groenhof
authors: Andreas W
authors: AW
authors: Ehlers
authors: Koop
authors: K
authors: Lammertsma
mesh_terms: D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry; D008956:Models, Chemical; D008958:Models, Molecular; D010100:Oxygen / Q000737:chemistry*; D011522:Protons; D013816:Thermodynamics
chemical_list: D011522:Protons; D003577:Cytochrome P-450 Enzyme System; D006861:Hydrogen Peroxide; D010100:Oxygen