Cytochrome P450 enzymes (CYP)

Cytochrome P450 (CYP) enzymes are a diverse superfamily of heme-containing proteins that serve as the primary system for the oxidative metabolism of drugs and other xenobiotics (Zanger & Schwab, 2013) [1.1.3]. Located predominantly in the endoplasmic reticulum of hepatocytes and enterocytes, these enzymes catalyze a wide range of reactions, including hydroxylation, epoxidation, and dealkylation (NIH, 2023) [1.2.1]. Beyond drug metabolism, CYPs are essential for the biosynthesis and degradation of endogenous molecules such as steroid hormones, cholesterol, and vitamins (MDPI, 2023) [1.2.3]. In clinical practice, CYPs are critical because their inhibition or induction by one drug can profoundly alter the plasma concentration and safety profile of another, leading to significant drug-drug interactions (FDA, 2023) [1.1.2]. Furthermore, genetic polymorphisms in CYP genes contribute to the wide inter-individual variability observed in drug efficacy and toxicity (Lynch & Price, 2007) [1.1.2]. The term "Other cytochrome P450 enzymes" typically refers to the broader group of isoforms that are not the primary focus of standard metabolic assays but still play significant roles in human physiology and pharmacology (Perepechaeva, 2022) [1.2.1].

Other names

CYP450Cytochrome P450 superfamilyHeme-thiolate proteinsMicrosomal monooxygenaseOther cytochrome P450 enzymes

Drugs interact with Cytochrome P450 enzymes through reversible or irreversible inhibition, which decreases the rate of metabolism for co-administered drugs, or through induction, which increases enzyme expression and accelerates drug clearance (Lynch & Price, 2007) [1.1.2]. Some drugs also serve as substrates, undergoing metabolic transformation into active or inactive forms (FDA, 2023) [1.1.2].