[Factors determining the selectivity of cytochrome P-450-catalyzed alkane oxidation].
Hexane oxidation by various liver microsomes fractions of noninduced and phenobarbitol- or methylcholantrene-induced rabbits (MR, MRPB, MRMC) has been studied. The relative reactivity of the C-H bond at the 1st, 2nd and 3rd carbon atoms has been shown to depend on the fraction nature and on the oxygen-activating system (NADPH/O2 or PhIO). The C3/C2 hexanol ratio is determined by steric factors of the hexane oxidation reaction. According to this parameter, the forms of cytochrome P-450 can be arranged in the following order: MRMC less than MRPB less than MR. The size of hydrophobic cavities connecting the substrate seems to decrease in the same order. The data obtained suggest that microsomes contain a cytochrome P-450 fraction which oxidizes alkanes only at the terminal methyl group. The regioselectivity of hexane oxidation in the P-450-NADPH-O2 and P-450-PhIO systems has been compared. These systems have been shown to generate different particles responsible for hydroxylation.
D000473:Alkanes / Q000378:metabolism*; D000818:Animals; D002384:Catalysis; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D006900:Hydroxylation; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology*; D010084:Oxidation-Reduction; D011817:Rabbits
D000473:Alkanes; D003577:Cytochrome P-450 Enzyme System
O prichinakh, opredeliaiushchikh selektivnost' v kataliziruemykh tsitokhromom P-450 reaktsiiakh okisleniia alkanov.