[Comparative study of 1-naphthol oxidation by cytochrome P-450 and oxyhemoglobin]

The kinetics of 1-naphthol oxidation by rat liver microsomes in a phosphate buffer (pH 7.6) with participation of NADPH and O2 were studied at 9.5-27 degrees C. The activation energy of 1-naphthol oxidation (12.6 +/- 1.0 kcal/mol) was determined from the temperature dependence of initial oxidation rates. The kinetics of 1-naphthol oxidation by oxyhemoglobin in a phosphate buffer (pH 8.0) were studied at 13-25.5 degrees C. The activation energy equal to 17.7 +/- 1.0 kcal/mol for 1-naphthol oxidation by oxyhemoglobin was determined. The differences in oxidation mechanisms in the reactions with participation of cytochrome P-450 and oxyhemoglobin are discussed. Oxyhemoglobin Fe3+O2- interacts via one-electron way, whereas the microsomal cytochrome P-450 complex Fe3+O22- interacts with 1-naphthol via a two-electron way.