CYP1A1 is a cytochrome P450 monooxygenase that catalyzes oxidation of diverse endogenous and exogenous substrates. Mechanistically, it uses molecular oxygen to insert one atom into substrates while reducing the second to water, with electrons supplied by NADPH via cytochrome P450 reductase 1. The enzyme exhibits high catalytic activity for estrogen metabolism, producing 2-hydroxy and 16-alpha-hydroxylated estrogens from estrone and estradiol 23. CYP1A1 catalyzes epoxidation of polyunsaturated fatty acids, converting arachidonic acid to epoxyeicosatrienoic acids (EETs) that function as vascular lipid mediators 4. Additionally, it catalyzes sequential oxidation of all-trans retinol to retinoic acid, potentially important for extrahepatic retinoic acid biosynthesis 1. Clinically, CYP1A1 plays a critical role in metabolizing carcinogenic polycyclic aromatic hydrocarbons (PAHs) including benzo[a]pyrene, with genetic polymorphisms potentially influencing cancer predisposition 5. Cigarette smoke components upregulate CYP1A1 expression, affecting estrogen metabolism and female fertility 6. Environmental pollutants including particulate matter and polychlorinated biphenyls induce CYP1A1 transcription and activity in lung and adipose tissues, triggering xenobiotic metabolism and oxidative stress responses 78. CYP1A1 metabolically activates aflatoxin B1 to genotoxic metabolites, with combined exposure to benzo[a]pyrene enhancing DNA damage 9. The enzyme functionally interacts with heme oxygenase-1 and NADPH-cytochrome P450 reductase, suggesting coordinated regulation of heme metabolism and detoxification pathways 10.