CYP3A4 Recombinant Rabbit mAb (S-2281-2)

CYP3A4 is a 57-kDa cytochrome P450 mono-oxygenase anchored in the endoplasmic reticulum of human liver and intestine, where its large, highly lipophilic active site binds a broad spectrum of substrates—including more than half of all marketed drugs—catalyzing the insertion of an oxygen atom into C–H or C=C bonds to increase polarity and facilitate elimination; expression is up-regulated by nuclear receptor PXR and down-regulated by inflammatory cytokines, leading to up to 40-fold inter-individual variability, and common genetic variants (e.g., *22) modestly alter activity, while potent inhibitors like ketoconazole or grapefruit furanocoumarins and inducers like rifampicin or St. John’s wort can precipitate clinical drug–drug interactions, making CYP3A4 a central determinant of systemic exposure, efficacy, and toxicity for statins, calcium-channel blockers, immunosuppressants, and many oncology agents.