title: Protein oxidation by the cytochrome P450 mixed-function oxidation system.
abstract: This mini-review summarizes results of studies on the oxidation of proteins and low-density lipoprotein (LDL) by various mixed-function oxidation (MFO) systems. Oxidation of LDL by the O2/FeCl3/H2O2/ascorbate MFO system is dependent on all four components and is much greater when reactions are carried out in the presence of a physiological bicarbonate/CO2 buffer system as compared to phosphate buffer. However, FeCl3 in this system could be replaced by hemin or the heme-containing protein, hemoglobin, or cytochrome c. Oxidation of LDL by the O2/cytochrome P450 cytochrome c reductase/NADPH/FeCl3 MFO system is only slightly higher (25%) in the bicarbonate/CO2 buffer as compared to phosphate buffer, but is dependent on all components except FeCl3. Omission of FeCl3 led to a 60% loss of activity. These results suggest that peroxymonobicarbonate and/or free radical derivatives of bicarbonate ion and/or CO2 might contribute to LDL oxidation by these MFO systems.
authors.affiliation: Laboratory of Biochemistry, National Heart, Lung, and Blood Institute, National Institutes of Health, Bethesda, MD 20892-8012, USA. erstadtman@nih.gov
authors.forename: Earl R
authors.initials: ER
authors.lastname: Stadtman
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Arai
authors.forename: Barbara S
authors.initials: BS
authors.lastname: Berlett
mesh_terms: D000818:Animals; D003577:Cytochrome P-450 Enzyme System / Q000737:chemistry* / Q000378:metabolism*; D006801:Humans; D015227:Lipid Peroxidation; D008077:Lipoproteins, LDL / Q000737:chemistry* / Q000378:metabolism*; D006899:Mixed Function Oxygenases / Q000737:chemistry / Q000378:metabolism / Q000502:physiology
chemical_list: D008077:Lipoproteins, LDL; D003577:Cytochrome P-450 Enzyme System; D006899:Mixed Function Oxygenases