NADPH-cytochrome P450 oxidoreductase transfers electrons from NADPH to cytochrome P450 and catalyzes the one-electron reduction of many drugs and foreign compounds. This enzyme is a flavoprotein containing the cofactors FMN and FAD, which are essential for its function. We have expressed the putative FMN and FAD/NADPH binding domains of P450 reductase and show that these distinct peptides fold ...

Cytochrome P450 is a family of isozymes responsible for the biotransformation of several drugs. Drug metabolism via the cytochrome P450 system has emerged as an important determinant in the occurrence of several drug interactions that can result in drug toxicities, reduced pharmacological effect, and adverse drug reactions. Recognizing whether the drugs involved act as enzyme substrates, induce...

The enzymic basis for intracellular reduction of N-hydroxylated amidines to their corresponding amidines, and hydroxylamines to their corresponding amines, is unknown. The hydroxylated amidines can be used as prodrug moieties, and an understanding of the enzyme system active in the reduction can contribute to more efficient drug development. In this study, we examined the properties of this enz...

A central feature in the biosynthesis of Taxol is oxygenation at multiple positions of the taxane core structure, reactions that are considered to be mediated by cytochrome P450-dependent monooxygenases. A PCR-based differential display-cloning approach, using Taxus (yew) cells induced for Taxol production, yielded a family of related cytochrome P450 genes, one of which was assigned as a taxane...

Caffeine and 7,8-benzoflavone activate CYP3A2 in rat liver microsomes. Both activators appear to enhance enzyme activity by an increase in Vmax and to a lesser extent a decrease in Km. Additive effect studies demonstrated that the two activators oppose one another's effect. Electron transfer steps in the cytochrome P450 cycle are involved in the mechanism of cytochrome P450 activation, as indic...

We describe the detailed biochemical characterization of CYP74C3 (cytochrome P450 subfamily 74C3), a recombinant plant cytochrome P450 enzyme with HPL (hydroperoxide lyase) activity from Medicago truncatula (barrel medic). Steady-state kinetic parameters, substrate and product specificities, RZ (Reinheitszahl or purity index), molar absorption coefficient, haem content, and new ligands for an H...

Abyssomicin C and its atropisomer are potent inhibitors of bacterial folate metabolism. They possess complex polycyclic structures, their biosynthesis has been shown to involve several unusual enzymatic transformations. Using a combination synthesis in vitro assays we reveal that AbyV, cytochrome P450 enzyme from the aby gene cluster, catalyses key late-stage epoxidation required for installati...

The effect of central nervous system inflammation on the levels and activity of hepatic and brain cytochrome P450 were examined in the rat. Brain ethoxyresorufin dealkylkase (EROD) was depressed during localized inflammatory responses evoked by lipopolysaccharide (LPS) injected into the lateral ventricle. This loss was accompanied by a concomitant loss of EROD activity and cytochrome P450 in li...

Cytochrome P450 proteins belong to one of the largest families enzyme in plants and play important roles plant growth development stress response. In our previous studies, a cytochrome gene, GhCYP94C1 (cytochrome 94C1), was functionally characterized as positive regulator seed germination, main root elongation early flowering. However, whether gene has other potential functions rem...

Cytochrome P450 (P450) enzyme expression patterns were determined for a panel of 60 human tumor cell lines, representing nine tumor tissue types, used by the National Cancer Institute (NCI) Anticancer Drug Screening Program. All 60 tumor cell lines displayed significant P450 activity, as well as P450 reductase activity, as determined using the general P450 substrate 7-benzyloxyresorufin. Cell l...