Cytochrome P450 family 1 subfamily A member (CYP1A)

Cytochrome P450 family 1 subfamily A (CYP1A) includes key enzymes such as CYP1A1 and CYP1A2, which are membrane-bound monooxygenases that catalyze the phase I metabolism of numerous xenobiotics and endogenous compounds. These enzymes introduce an oxygen atom into substrates, aiding in drug detoxification, metabolic activation of procarcinogens, and general biotransformation. CYP1A1, for example, is crucial in the metabolic activation of polycyclic aromatic hydrocarbons like benzo[a]pyrene, converting them to reactive, often carcinogenic, intermediates. CYP1A enzymes are expressed mainly in the liver but also found in the intestine, lungs, and other tissues. They are essential in pharmacogenomics due to their variable activity between individuals, affecting responses to drugs and susceptibility to chemical-induced diseases. Induction of CYP1A1 and CYP1A2 is widely used as a biomarker of exposure to certain environmental pollutants that act through the aryl hydrocarbon receptor. Both induction and inhibition of CYP1A can cause clinically relevant pharmacokinetic drug–drug interactions and influence disease processes, notably in cancer risk.

Other names

Cytochrome P450 1ACYP1A subfamilyAryl hydrocarbon hydroxylase (historical, especially for CYP1A1)Monooxygenase (family category)

Inhibition of CYP1A slows metabolism of CYP1A substrates, potentially increasing their plasma concentration and risk of toxicity. Induction of CYP1A enhances metabolism of CYP1A substrates, potentially reducing drug efficacy or activating procarcinogens to carcinogenic metabolites.