Purification and characterization of microsomal cytochrome P-450s

Guengerich, F. Peter; Dannan, Ghazi A.; Wright, S.; Martin, Martha V.; Kaminsky, Laurence S.

doi:10.3109/00498258209038945

Cited by 165 publications

(61 citation statements)

References 82 publications

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“…Measurement of Cytochrome P450 Content-The CYP contents of mitochondrial and microsome membranes were measured by the difference spectra of carbon monoxide (CO)-treated and dithionite-reduced samples as described by Omura and Sato (57,58) and as modified by Guengerich (59,60), using a dual beam spectrophotometer (Cary 1E; Varian, Walnut Creek, CA). Mitochondrial or microsomal (0.4 mg) proteins were solubilized in potassium phosphate buffer (0.1 M, pH 7.4) containing 1 mM EDTA, 20% glycerol (v/v), sodium cholate (0.5%, w/v), and Triton N-101 (0.4%, w/v).…”

Section: Methodsmentioning

confidence: 99%

Human Cytochrome P450 2E1 Mutations That Alter Mitochondrial Targeting Efficiency and Susceptibility to Ethanol-induced Toxicity in Cellular Models

Bansal

Anandatheerthavarada

Prabu

et al. 2013

Journal of Biological Chemistry

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Background: Induced expression of CYP2E1 is known to enhance alcohol liver toxicity. Results: Novel mutations W23R/W30R and L32N in human CYP2E1 alter mitochondrial and microsomal targeting efficiency. Conclusion: Human variants with altered targeting modulate susceptibility of cells to alcohol. Significance: Carriers of the novel W23R/W30R mutation in CYP2E1 are likely to be more susceptible to alcohol toxicity.

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Section: Methodsmentioning

confidence: 99%

Human Cytochrome P450 2E1 Mutations That Alter Mitochondrial Targeting Efficiency and Susceptibility to Ethanol-induced Toxicity in Cellular Models

Bansal

Anandatheerthavarada

Prabu

et al. 2013

Journal of Biological Chemistry

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“…Immunochemical quantification of P-450 male and P-450-female: A peroxidase staining technique coupled with SDS-polyacrylamide gel electrophoresis (Western blot) was used to quantitate the content of P-450-male and P-450-female in hepatic microsomes (5,22). The characteristics of P-450-male, P-450 female and monospecific antibodies to these cytochromes were described previously (9,22).…”

Section: Animalsmentioning

confidence: 99%

Effects of Hypophysectomy and Growth Hormone Treatment on Sex-Specific Forms of Cytochrome P-450 in Relation to Drug and Steroid Metabolisms in Rat Liver Microsomes

Yamazoe

Shimada

Kamataki

et al. 1986

Japanese Journal of Pharmacology

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Abstract-Hypophysectomy decreased the content of a male specific cytochrome P-450, P-450-male, in male rats, while it expressed P-450-male and completely depressed a female specific cytochrome P-450, P-450-female, in female rats. Intermittent injections of human growth hormone (GH), which mimic the secretion in males, restored P-450-male in hypophysectomized (Hypox) male rats and partially restored P-450-female in Hypox female rats. Continuous infusion of GH, which mimics the female secretion pattern, into Hypox male rats caused a further decrease in P-450-male content, and it caused the expression of P-450-female. In Hypox female rats, the same treatment depressed P-450-male and expressed P-450-female to the level of an intact female. These results indicate that the diurnal changes in the pattern of serum growth hormone level regulate the expression of P-450-male and P-450-female. The activities of testosterone 2a and 16a hydroxylases were closely correlated to P-450-male content with the correlation coefficients (r) of 0.955 and 0.929, respectively. Benzo(a)pyrene hydroxylation was also correlated to P-450-male content (r=0.850).Aminopyrine N-deme thylation and propoxycoumarin 0-depropylation were correlated to less extents (r=0.692 and r=0.720), while aniline hydroxylation and 0-ethylresorufin 0 deethylation were not correlated to P-450-male content. These results indicate that testosterone 2a and 16a-hydroxylations are closely dependent, but the metabolism of a variety of drugs are dependent to different extents on P-450-male in rat liver microsomes.

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“…of) cytochromes P450 (Guengerich et al, 1982;Beaune et al, 1986;Kaminsky, 1989). Various P450 isozymes, displaying different regio-and stereoselectivities, have been shown to be involved in the metabolism of warfarin (Guengerich et al, 1982;Rettie et al, 1992). The variety of warfarin metabolizing P450 isozymes offers an explanation for the stereoselective (pharmacokinetic) drug-interactions with R-warfarin (Choonara et al, 1986;Toon et al, 1987;Sutfin et al, 1989;), S-warfarin (Lewis et al, 1974;O'Reilly, 1980), as well as non-stereoselective interactions (O'Reilly et al, 1987) that have been observed.…”

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Human liver microsomal metabolism of the enantiomers of warfarin and acenocoumarol: P450 isozyme diversity determines the differences in their pharmacokinetics

Hermans

Thijssen

1993

British J Pharmacology

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1 To explain the large differences in (the stereoselectivity of) the clearances of the enantiomers of warfarin and acenocoumarol (4'-nitrowarfarin) their human liver microsomal metabolism has been studied and enzyme kinetic parameters determined. The effects of cimetidine, propafenone, sulphaphenazole, and omeprazole on their metabolism has been investigated. 2 The 4-hydroxycoumarins follow similar metabolic routes and are mainly hydroxylated at the 6-and 7-position (accounting for 63 to 99% of the metabolic clearances).3 Due to the lower Km values of R-and S-acenocoumarol and higher Vma. values of S-acenocoumarol, the overall metabolic clearances of R/S acenocoumarol exceed those of R/S warfarin 6 and 66 times respectively. 4 The metabolism of both compounds is stereoselective for the S-enantiomers, which is 10 times more pronounced in the case of acenocoumarol.5 Except for the 7-hydroxylation of the R-enantiomers (r = 0.90; P <0.025), the 6-and 7-hydroxylation rates of R/S warfarin do not correlate with those of R/S acenocoumarol. 6 Sulphaphenazole competitively inhibits the 7-and in some samples partly (up to 50%) the 6-hydroxylation of S-warfarin as well as the 7-hydroxylation of R-and S-acenocoumarol and the 6-hydroxylation of S-acenocoumarol (Kis ranging from 0.5-1.3 JAM).7 Omeprazole partly (40-80%) inhibits the 6-and 7-hydroxylation of R-warfarin (Ki = 99 and 117 pM) and of R-(Ki = 219 and 7.2 jAM) and S-acenocoumarol (Ki = 6.1 and 7.7 JiM) but not S-warfarin in a competitive manner. 8 Differences in the partial (up to 40%) inhibition of the metabolism of the enantiomers of the 4-hydroxycoumarins were also observed for the relatively weak inhibitors, propafenone and cimetidine. 9 The results suggest that the coumarin ring hydroxylations of both compounds are catalysed by different combinations of P450 isozymes. The 7-hydroxylation of R/S acenocoumarol and the 6-hydroxylation of S-acenocoumarol are at least partly conducted by (a) P450 isozyme(s) of the 2C subfamily different from P450 2C9 (the main S-warfarin 7-and 6-hydroxylase).

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Purification and characterization of microsomal cytochrome P-450s

Cited by 165 publications

References 82 publications

Human Cytochrome P450 2E1 Mutations That Alter Mitochondrial Targeting Efficiency and Susceptibility to Ethanol-induced Toxicity in Cellular Models

Human Cytochrome P450 2E1 Mutations That Alter Mitochondrial Targeting Efficiency and Susceptibility to Ethanol-induced Toxicity in Cellular Models

Effects of Hypophysectomy and Growth Hormone Treatment on Sex-Specific Forms of Cytochrome P-450 in Relation to Drug and Steroid Metabolisms in Rat Liver Microsomes

Human liver microsomal metabolism of the enantiomers of warfarin and acenocoumarol: P450 isozyme diversity determines the differences in their pharmacokinetics

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