CYP1A2

Cytochrome P450 1A2 (abbreviated CYP1A2), a member of the is_associated_with::cytochrome P450 mixed-function oxidase system, is involved in the metabolism of is_associated_with::xenobiotics in the body. In humans, the CYP1A2 enzyme is encoded by the CYP1A2 is_associated_with::gene.

Function
CYP1A2 is a member of the is_associated_with::cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are is_associated_with::monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. CYP1A2 localizes to the is_associated_with::endoplasmic reticulum and its expression is induced by some is_associated_with::polycyclic aromatic hydrocarbons (PAHs), some of which are found in cigarette smoke. The enzyme's endogenous substrate is unknown; however, it is able to metabolize some PAHs to carcinogenic intermediates. Other xenobiotic substrates for this enzyme include is_associated_with::caffeine, aflatoxin B1, and is_associated_with::acetaminophen. The transcript from this gene contains four Alu sequences flanked by direct repeats in the 3' untranslated region.

Effect of diet
Expression of CYP1A2 appears to be induced by various dietary constituents. Vegetables such as cabbages, cauliflower and broccoli are known to increase levels of CYP1A2. Lower activity of CYP1A2 in South Asians appears to be due to cooking these vegetables in curries using ingredients such as is_associated_with::cumin and is_associated_with::turmeric, ingredients known to inhibit the enzyme.

Ligands
Following is a table of selected substrates, inducers and inhibitors of CYP1A2.

Inhibitors of CYP1A2 can be classified by their potency, such as:
 * Strong inhibitor being one that causes at least a 5-fold increase in the plasma AUC values, or more than 80% decrease in clearance.
 * Moderate inhibitor being one that causes at least a 2-fold increase in the plasma AUC values, or 50-80% decrease in clearance.
 * Weak inhibitor being one that causes at least a 1.25-fold but less than 2-fold increase in the plasma AUC values, or 20-50% decrease in clearance.