addition of n-butyl nitrite to isolated rat hepatocytes caused an immediate glutathione depletion followed by an inhibition of mitochondrial respiration, inhi- bition of glycolysis and atp depletion. at cytotoxic butyl nitrite concentrations, lipid  peroxidation  occurred  before  the  plasma  membrane  was  disrupted. cytochrome p-450 inhibitors inhibited peroxynitrite formation and prevented ...

An intraperitoneal dose of CS(2) (500mg/kg) to male rats resulted in loss of liver microsomal mixed-function-oxidase activity (85% loss of biphenyl 4-hydroxylase), followed by denaturation of liver cytochrome P-450 to cytochrome P-420, and degradative loss of both cytochromes (50% loss). Losses of NADPH-cytochrome c reductase (20%) and cytochrome b(5) were considerably less. Intraperitoneal adm...

The hydroxyl radical-mediated oxidation of 5,S-dimethyl1-pyrroline N-oxide, benzene, ketomethiolbutyric acid, deoxyribose, and ethanol, as well as superoxide anion and hydrogen peroxide formation was quantitated in reconstituted membrane vesicle systems containing purified rabbit liver microsomal NADPHcytochrome P-450 reductase and cytochromes P-450 LM2, P-450 LMeb, or P-450 LM4, and in vesicle...

The role of haem synthesis during induction of hepatic cytochrome P-450 haemoproteins was studied in chick embryos in ovo and in chick embryo hepatocytes cultured under chemically defined conditions. 1. Phenobarbitone caused a prompt increase in the activity of 5-aminolaevulinate synthase, the rate-limiting enzyme of haem biosynthesis, and in the concentration of cytochrome P-450. This inductio...

The appearance of cytochrome P-450 in the yeast Saccharomyces cerevisiae depended on the substrate supporting growth. Cytochrome P-450 was apparent in yeast cells grown on a strongly fermentable sugar such as D-glucose, D-fructose or sucrose. When yeast was grown on D-galactose, D-mannose or maltose, where fermentation and respiration occurred concomitantly, cytochrome P-450 was also formed. Th...

The association between murine cytochrome P3-450 and hepatic aflatoxin B1-4-hydroxylase, a cytochrome P-450-dependent enzyme which converts aflatoxin B1 (AFB1) to aflatoxin M1 (AFM1), was examined by (a) purification of the cytochrome P-450 which preferentially metabolizes AFB1 to AFM1; (b) isolation of the specific cDNA clone; and (c) correlating induction of transcriptional activation of the ...

Rational approaches have been extensively used to investigate the role of active site residues in cytochrome P450 (CYP) functions. However, recent studies using random mutagenesis suggest an important role for non-active site residues in CYP functions. Meta-analysis of the random mutants showed that 75% of the functionally important non-active site residues are present in 20% of the entire prot...

We expressed mouse cytochrome P1-450 and P3-450 using recombinant vaccinia virus gene expression system in HeLa cells that were devoid of significant basal levels of P-450. HeLa cells were infected with the recombinant vaccinia virus containing either mouse cytochrome P1-450 or P3-450 cDNA, and the cell lysates were analyzed for the kinetics of P-450 enzyme activity and protein expression at th...

Three highly purified forms of rat liver microsomal cytochrome P-450 (P-450,, P-45Ob, P-450,) are shown to be distinct proteins based on comparisons of their amino acid compositions, automated sequence analyses of the first 19 amino acids, and carboxypeptidase analyses of the COOH-terminal sequences. These three forms of cytochrome P-450 were purified from liver microsomes of rats pretreated wi...