The cytochrome P450 family of enzymes has long been known tometabolize a wide range of compounds, including many of today’s most common drugs. A novel nuclear receptor called PXR has been established as an activator of several of the cytochrome P450 genes, including CYP3A4. This enzyme is believed to account for the metabolism of more than 50% of all prescription drugs. PXR is therefore used as a negative selector target and discriminatory filter in preclinical drug development.
