Cytochrome P450 family 1 subfamily A (CYP1A) (CYP1A)

Cytochrome P450 1A (CYP1A) is a subfamily of the cytochrome P450 superfamily of heme-thiolate monooxygenases, consisting primarily of the CYP1A1 and CYP1A2 isoforms in humans [7, 10, 22]. These enzymes play a pivotal role in the Phase I metabolism of diverse xenobiotics, including environmental pollutants, dietary compounds, and therapeutic drugs [1, 11, 12]. CYP1A2 is predominantly expressed in the liver and is responsible for the metabolism of approximately 10-15% of clinically used drugs, such as caffeine, theophylline, and clozapine [7, 13, 22]. In contrast, CYP1A1 is mainly expressed in extrahepatic tissues like the lungs and gastrointestinal tract, where it is well-known for its role in the metabolic activation of pro-carcinogens, such as polycyclic aromatic hydrocarbons found in cigarette smoke, into highly reactive DNA-adducting intermediates [11, 13, 22]. Both enzymes are highly inducible via the aryl hydrocarbon receptor (AhR) signaling pathway [1, 11, 13]. Due to their significant involvement in drug clearance and toxification, CYP1A enzymes are critical considerations in drug development for predicting drug-drug interactions and assessing individual susceptibility to chemical carcinogenesis [1, 8, 9, 18].

Other names

CYP1ACytochrome P450 1A subfamilyP450 1AAryl hydrocarbon hydroxylase

Substrate oxidation via monooxygenation, competitive inhibition, and transcriptional induction via the aryl hydrocarbon receptor