AIMS We previously reported the effect of St John's wort (Hypericum perforatum) standardised extract LI 160 on the activities of cytochrome P450 2C6, 2D2 and 3As (Dostalek et al., Life Sciences 2005;78(3):239-44). In this study, we aimed to assess the effect of St John's wort on the activity of cytochrome P450 1A2. METHODS The isolated perfused rat liver model was used in our experiments with...

We are constantly exposed to many potentially toxic chemicals. Most require metabolic activation to species responsible for cell injury. Although cytochrome P450 2E1 is only one of many different forms of cytochrome P450 that catalyze these reactions, it has an important role in human health as a result of being readily induced by acute and chronic alcohol ingestion. The enzyme efficiently cata...

When various p-substituted phenols (substituent = NO2, CN, CH2OH, COCH3, COPh, COOH, F, Cl, and Br) were incubated with rat liver microsomes, the substituent was eliminated to produce hydroquinone, and the reaction was inhibited by CO and a cytochrome P450-specific inhibitor. In the case of p-cresol (substituent = CH3), p-toluquinol was formed instead of hydroquinone. Experiments using 18O2 pro...

Bursaphelenchus xylophilus, the causal agent of pine wilt disease, causes huge economic losses in pine forests. The high expression of cytochrome P450 genes in B. xylophilus during infection in P. thunbergii indicated that these genes had a certain relationship with the pathogenic process of B. xylophilus. Thus, we attempted to identify the molecular characterization and functions of cytochrome...

Previous studies have shown that the presence of one P450 enzyme can affect the function of another. The goal of the present study was to determine if P450 enzymes are capable of forming homomeric complexes that affect P450 function. To address this problem, the catalytic activities of several P450s were examined in reconstituted systems containing NADPH-POR (cytochrome P450 reductase) and a si...

Mammalian cytochrome 1'-450 exists as a multigene family expressing a spectrum of structurally and functionally distinct isoenzymes involved in the biotransformation of both exogenous and endogenous substrates [ l , 21. Although a generally accepted isoenzyme nomenclature based on divergent evolution and nucleotide/amino acid homologies is now widely used [I], i t is still useful, under certain...

We demonstrated recently that cytochrome b(5) plays an important in vivo role in hepatic cytochrome P450 (P450) function [J Biol Chem 283:31385-31393, 2008]. We have now generated a model in which cytochrome b(5) has been deleted in all tissues [cytochrome b(5) complete null (BCN)], which surprisingly results in a viable mouse despite the putative in vivo roles of this protein in lipid and ster...