What is the CYP2A6 enzyme?
What is the CYP2A6 enzyme?
CYP2A6 is the primary enzyme responsible for the oxidation of nicotine and cotinine. The CYP2A6 gene is part of a large cluster of cytochrome P450 genes from the CYP2A, CYP2B and CYP2F subfamilies on chromosome 19q. The gene was formerly referred to as CYP2A3; however, it has been renamed CYP2A6.
What drugs are metabolized by CYP2A6?
CYP2A6, a phase I drug metabolizing enzyme (DME) which metabolizes about 3% of pharmaceutical agents including letrozole, tegafur, coumarin, valproic acid, methoxyflurane, artesunate, disulfiram, halothane and fadrozole.
Which drug is an inhibitor of cytochrome P450 enzymes?
Significant Cytochrome P450 Enzymes and Their Inhibitors, Inducers, and Substrates
| Enzyme | Potent inhibitors* |
|---|---|
| CYP2C19 | Fluvoxamine, isoniazid (INH), ritonavir |
| CYP2D6 | Amiodarone, cimetidine, diphenhydramine (Benadryl), fluoxetine, paroxetine (Paxil), quinidine, ritonavir, terbinafine (Lamisil) |
| CYP3A4 and CYP3A5 |
Where is CYP2A6 found?
the liver
CYP2A6 expression is mainly found in the liver, but its protein or mRNA is also expressed in other tissues such as nasal epithelium, trachea, lung and esophagus [6]–[7]. There are 31 numbered CYP2A6 allelic variants identified to date, however, not all have been functionally characterized.
What does CYP1A2 metabolize?
CYP1A2 metabolizes endogenous compounds such as retinols, melatonin, steroids, uroporphyrinogen and arachidonic acids and plays a major role in procarcinogen activation and DDIs, due to induction and inhibition by several therapeutic drugs.
What’s nicotine do?
When humans, mammals, and most other types of animals are exposed to nicotine, it increases their heart rate, heart muscle oxygen consumption rate, and heart stroke volume. These are known as pharmacologic effects. Consuming nicotine is also linked to raised alertness, euphoria, and a sensation of being relaxed.
What is nicotine metabolized by?
Almost 90% of nicotine absorbed by the body is metabolized in the liver. Nicotine may also be metabolized in the kidneys, lungs, brain, and respiratory epithelium membranes.
What drugs are CYP3A inhibitors?
CYP3A inducers include the glucocorticoids, rifampin, carbamazepine, phenobarbital, and phenytoin. Among the many significant CYP3A inhibitors are grapefruit juice, erythromycin, ketoconazole, clarithromycin, and verapamil.
Is primidone a PGP inducer?
Carbamazepine, phenytoin, phenobarbital and primidone are strong inducers of cytochrome P450 and glucuronizing enzymes (as well as P-glycoprotein) and can reduce the efficacy of co-administered medications such as oral anticoagulants, calcium antagonists, steroids, antimicrobial and antineoplastic drugs through this …
What metabolizes CYP2A6?
What drugs does CYP1A2 metabolize?
CYP1A2 plays an important role in metabolism of drugs like clozapine, olanzapine, fluvoxamine, haloperidol, theophylline; biotransformation of endogenous compounds like melatonin, bilirubin, estrogens, procarcinogens, aflatoxin B1, and aromatic/heterocyclic amines as well as caffeine (Gunes and Dahl, 2008).
Is melatonin a CYP1A2 inhibitor?
Earlier evidence suggests that melatonin is almost exclusively metabolised by CYP1A2 and could serve as a probe drug for CYP1A2 phenotyping. However, caffeine inhibits the metabolism of melatonin by CYP1A2 and dietary caffeine could be a potential confounder for the measurement of CYP1A2 activity with melatonin.
What kind of enzymes does CYP2A6 encode?
This gene, CYP2A6, encodes a member of the cytochrome P450 superfamily of enzymes. The cytochrome P450 proteins are monooxygenases which catalyze many reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids.
What is the role of CYP2A6 in AIDS?
CYP2B6/CYP2A6 genotypes were associated with increased reported suicidality among AIDS patients who had been randomly assigned to receive efavirenz-containing regimens in clinical trials. Strength of association varied by race/ethnicity. The CYP2A6 gene product plays a major role in the nicotine metabolism pathway, which influences nicotine intake.
What is the effect of kinsenoside on CYP2A6?
The effect of kinsenoside was negligible on the enzyme activity of all the CYP isozymes tested even though CYP2A6 was slightly inhibited at higher concentrations. CYP2A6 gene variants were associated with markedly reduced nicotine and cotinine clearances. CYP2A6 polymorphisms are associated with poor response to chemotherapy in gastric cancer.
What is the role of CYP2A6 in lung cancer?
Strength of association varied by race/ethnicity. The CYP2A6 gene product plays a major role in the nicotine metabolism pathway, which influences nicotine intake. CYP2A6 activity provides information on lung cancer risk that is not captured by smoking history.