title: Dimethylnitrosamine demethylation by reconstituted liver microsomal cytochrome P-450 enzyme system.
abstract: Oxidative demethylation of dimethylnitosamine was studied with both reconstituted and unresolved liver microsomal cytochrome P-450 enzyme systems from rats and hamsters. Proteinase treatment of liver microsomal preparations yielded cytochrome P-450 particulate fractions. Both cytochrome P-450 and NADPH- cytochrome c reductase fractions were required for optimum demethylation activity. Particulate cytochrome P-450 fractions were more effecient than either Triton X-100- or cholatesolubilized preparations of these particles in demethylation activity with rat and hamster liver preparations appear to be due to differences in specificity in their cytochrome P-450 fractions.
mesh_terms: D000818:Animals; D006224:Cricetinae; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D004128:Dimethylnitrosamine / Q000378:metabolism*; D008297:Male; D008862:Microsomes, Liver / Q000201:enzymology*; D009251:NADPH-Ferrihemoprotein Reductase / Q000378:metabolism; D009602:Nitrosamines / Q000378:metabolism*; D051381:Rats
chemical_list: D009602:Nitrosamines; D003577:Cytochrome P-450 Enzyme System; D009251:NADPH-Ferrihemoprotein Reductase; D004128:Dimethylnitrosamine