The role of glutathione and cytochrome P-450 in the production of DNA damage by chromium(VI) was examined in chicken embryo hepatocytes by the alkaline elution technique. Cellular levels of glutathione and cytochrome P-450 were altered by treating the hepatocytes with N-acetyl-L-cysteine, buthionine sulfoximine, isopentanol, or beta-naphthoflavone. A dramatic increase in chromium(VI)-induced DN...

A new procedure for obtaining rat lung microsomes essentially free of interfering hemoproteins has been developed. The method includes Sepharose 2B column chromatography of the 12,000 • g supernatant of lung homogehates, followed by ultracentrifugation of the material eluted in the void volume. Microsomes isolated in this manner contain specific levels of cytochromes bs and P-450 and of NADPH-c...

Highly purified isozymes of cytochrome P-450 catalyzed the formation of 3-glutathion-S-ylacetaminophen (GS-APAP) and 3-hydroxyacetaminophen (3-OH-APAP) from acetaminophen (APAP). A major isozyme from untreated male rats (P-450UT-A) catalyzed the formation of ca. 2.0 nmol/nmol of P-450/10 min of 3-OH-APAP and approximately 7.2 nmol of GS-APAP/nmol of P-450/10 min. Antibodies specific for cytochr...

Metabolic activation of phenacetin by liver microsomes proceeds via both phenetidine and N-hydroxyphenacetin to direct-acting mutagens, i.e., N-hydroxyphenetidine and p-nitrosophenetole. Five different molecular species of cytochrome P-450 have been purified from liver microsomes of drug-pretreated Wistar rats or Syrian hamsters and their abilities to activate phenetidine and phenacetin were co...

Presented here are the results of recent studies wfii-&-Gre designed to: ( 1 ) evaluate the role of the thiolate ligand, which is characteristic of P-450 structure, by incorporating it into model systems; ( 2 ) synthesize polypeptide-bound porphyrin to investigate the effects of heme environment on the activities; ( 3 ) apply appropriately designed P-450 mimics to drug metabolism studies and ev...

The presence of cytochrome P-450 and associated mono-oxygenase activities was examined in brain microsomes from male and female mice. Although the cytochrome P-450 level in male mouse brain was very low as compared with mouse liver, the aminopyrine N-demethylase and morphine N-demethylase specific activities in male mouse brain were much higher than those observed in mouse liver. Ethoxycoumarin...

The interaction between P-450czl and NADPH-cytochrome P-450 reductase, both purified from bovine adrenocortical microsomes, has been investigated in a reconstituted system with a nonionic detergent, Emulgen 913, by kinetic analysis and gel filtrations. Steady state kinetic data in progesterone 2 1-hydroxylation showed formation of an equimolar complex between the two enzyme proteins at low Emul...