CYPenzimektlmediated

CYPenzimektlmediated refers to biological processes mediated by cytochrome P450 enzymes, a large and diverse superfamily of heme-containing monooxygenases. In pharmacology and toxicology, the term is commonly used to describe the oxidative metabolism by CYP enzymes that transforms drugs, environmental chemicals, and certain endogenous substrates into more polar metabolites for elimination.

The enzymes catalyze monooxygenation reactions that require NADPH and molecular oxygen. The catalytic cycle involves electron transfer from NADPH via P450 reductase, substrate binding, oxygen activation, and insertion of one oxygen atom into the substrate. Reactions include hydroxylation, epoxidation, N- and O-dealkylation, deamination, and sulfoxidation.

Most CYP enzymes are expressed in the liver, with significant activity in the intestine and other tissues. The most important isoforms for drug metabolism are CYP3A4/5, CYP2D6, CYP2C9, CYP1A2, and CYP2C19, among others. Expression and activity vary with genetics, age, sex, environment, diet, and concomitant substances.

Clinical relevance includes variability in drug clearance, potential drug–drug interactions, and adverse effects. Inhibitors such as ketoconazole and certain protease inhibitors can reduce metabolism, while inducers like rifampin and St. John’s wort can increase it. Cytochrome P450 activity also influences prodrug activation, necessitating dose adjustments.

Beyond xenobiotics, CYP enzymes metabolize endogenous substrates, including steroids, fatty acids, and bile acids. In research and drug development, CYP-mediated metabolism is a key factor in predicting pharmacokinetics, drug design, and toxicity screening, using in vitro assays with recombinant enzymes and hepatocytes.