Kinetics of electron transfer between NADPH-cytochrome P450 reductase and cytochrome P450 3A4
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چکیده
منابع مشابه
Kinetics of electron transfer between NADPH-cytochrome P450 reductase and cytochrome P450 3A4.
We have incorporated CYP3A4 (cytochrome P450 3A4) and CPR (NADPH-cytochrome P450 reductase) into liposomes with a high lipid/protein ratio by an improved method. In the purified proteoliposomes, CYP3A4 binds testosterone with Kd (app)=36±6 μM and Hill coefficient=1.5±0.3, and 75±4% of the CYP3A4 can be reduced by NADPH in the presence of testosterone. Transfer of the first electron from CPR to ...
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Experiments demonstrating that cytochrome (cyt) b5 inhibits the activity of cytochrome P450 2B4 (cyt P450 2B4) at higher concentrations suggested that cyt b5 was occupying the cyt P450 reductase-binding site on cyt P450 2B4 and preventing the reduction of ferric cyt P450 (Zhang, H., Im, S.-C., and Waskell, L. (2007) J. Biol. Chem. 282, 29766-29776). In this work experiments were undertaken with...
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Cytochrome P450 (P450) 2S1 is one of the orphan P450s without a clear physiological function. Controversy has arisen as to whether it can interact with NADPH-P450 reductase and accept electrons. The reduction of 1,4-bis{[2-(dimethylamino-N-oxide)ethyl]amino}-5,8-dihydroxyanthracene-9,10-dione (AQ4N) by P450 2S1 was confirmed, and the NADPH consumption rates were measured aerobically and anaerob...
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Cytochrome P450 reductase (CPR) is a diflavin enzyme responsible for electron donation to mammalian cytochrome P450 enzymes in the endoplasmic reticulum. Dissection of the enzyme into functional domains and studies by site-directed mutagenesis have enabled detailed characterization of the mechanism of electron transfer using stopped-flow and equilibrium-perturbation methods, and redox potentiom...
متن کاملQuantitative analyses of electrostatic interactions between NADPH-cytochrome P450 reductase and cytochrome P450 enzymes.
A decline in the ionic interactions in the medium with increasing ionic strength (decrease in the ionic activity coefficients) was accompanied by an increase in the fast phase rate constants of CYP2B4 and CYP1A2 reduction. The stimulations were observed both in reconstituted P450 systems and in microsomes. An increase in the ionic strength from 10 to 100 mM sodium phosphate resulted in a 7-fold...
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ژورنال
عنوان ژورنال: Biochemical Journal
سال: 2010
ISSN: 0264-6021,1470-8728
DOI: 10.1042/bj20100744