title: Cytochrome p450 compound I.
abstract: Cytochrome P450 enzymes (P450s) comprise a large class of enzymes that effect numerous oxidations in nature. The active oxidants in P450s are thought to be iron(IV)-oxo porphyrin radical cations termed Compounds I, and these intermediates have been sought since the discovery of P450s 40 years ago. We report formation of the Compound I derivative of a P450 enzyme by laser flash photolysis oxidation of the corresponding Compound II species, an iron(IV)-oxo neutral porphyrin intermediate. The Compound II derivative in turn was produced by oxidation of the P450 with peroxynitrite, which effected a net one-electron, oxo-transfer reaction to the iron(III) atom of the resting enzyme. For the P450 studied in this work, CYP119 from the thermophile Sulfolobus solfactaricus, the P450 Compound II derivative was stable for seconds at ambient temperature, and the Compound I transient decayed with a lifetime of ca. 200 ms.
authors.affiliation: Department of Chemistry, University of Illinois at Chicago, Chicago, Illinois 60607, USA. men@uic.edu
authors.forename: Martin
authors.initials: M
authors.lastname: Newcomb
authors.forename: Rui
authors.initials: R
authors.lastname: Zhang
authors.forename: R Esala P
authors.initials: RE
authors.lastname: Chandrasena
authors.forename: James A
authors.initials: JA
authors.lastname: Halgrimson
authors.forename: John H
authors.initials: JH
authors.lastname: Horner
authors.forename: Thomas M
authors.initials: TM
authors.lastname: Makris
authors.forename: Stephen G
authors.initials: SG
authors.lastname: Sligar
mesh_terms: D019843:Archaeal Proteins; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry*; D010084:Oxidation-Reduction; D010105:Oxygenases / Q000737:chemistry*; D030421:Peroxynitrous Acid / Q000737:chemistry; D010777:Photochemistry; D013057:Spectrum Analysis; D048229:Sulfolobus solfataricus / Q000201:enzymology
chemical_list: D019843:Archaeal Proteins; D030421:Peroxynitrous Acid; D003577:Cytochrome P-450 Enzyme System; D010105:Oxygenases; C408874:CYP119 protein, Sulfolobus solfataricus