Cytochrome P450

The CYP450 family of enzymes account for the majority of phase I metabolism. Profiling test compounds with individual CYP450 isoforms provides important information regarding metabolism and can be useful as quick screens for lead optimization. In addition, CYP450 inhibition is a common cause for drug-drug interactions. The inhibition of a particular CYP450 isoform by a test compound may lead to potentially harmful accumulations of other drugs that are normally metabolized by the inhibited CYP450. Thus, it is important to understand and quantify the effect of test compounds on CYP450 activity.

CYP450 Profiling
Incubation solutions are prepared containing the individual human recombinant CYP450 isoform. The reaction is initiated with the addition of the co-factor NADPH and an aliquot of the solution is taken at pre-determined intervals. The peak area of the test compound at each time point is compared to the peak area of the time zero sample. A control reaction (without co-factor NADPH) is used in order to assess the amount of thermal breakdown, insolubility and non-specific binding that contributes to the overall loss of the test compound.

CYP450 Inhibition
Solutions of specific CYP450 isoforms and their associated substrate are generated with a range of test compound concentrations. The reaction is initiated with the addition of the co-factor NADPH and following incubation, the reaction is quenched. The dose-response curve for each isoform is generated to determine the extent of CYP450 inhibition, if any, by the test compound.