Cytochrome P450 2A6 (abbreviated CYP2A6) is a member of the
cytochrome P450
Cytochromes P450 (CYPs) are a Protein superfamily, superfamily of enzymes containing heme as a cofactor (biochemistry), cofactor that functions as monooxygenases. In mammals, these proteins oxidize steroids, fatty acids, and xenobiotics, and are ...
mixed-function oxidase system, which is involved in the metabolism of
xenobiotic
A xenobiotic is a chemical substance found within an organism that is not naturally produced or expected to be present within the organism. It can also cover substances that are present in much higher concentrations than are usual. Natural compo ...
s in the body. CYP2A6 is the primary enzyme responsible for the oxidation of
nicotine
Nicotine is a natural product, naturally produced alkaloid in the nightshade family of plants (most predominantly in tobacco and ''Duboisia hopwoodii'') and is widely used recreational drug use, recreationally as a stimulant and anxiolytic. As ...
and
cotinine. It is also involved in the metabolism of several pharmaceuticals, carcinogens, and a number of coumarin-type alkaloids. CYP2A6 is the only enzyme in the human body that appreciably catalyzes the 7-hydroxylation of
coumarin
Coumarin () or 2''H''-chromen-2-one is an aromatic organic chemical compound with formula . Its molecule can be described as a benzene molecule with two adjacent hydrogen atoms replaced by a lactone-like chain , forming a second six-membered h ...
, such that the formation of the product of this reaction, 7-hydroxycoumarin, is used as a probe for CYP2A6 activity.
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.
Interactive pathway map
Distribution
CYP2A6 localizes to the
endoplasmic reticulum
The endoplasmic reticulum (ER) is, in essence, the transportation system of the eukaryotic cell, and has many other important functions such as protein folding. It is a type of organelle made up of two subunits – rough endoplasmic reticulum ( ...
and is found predominantly in the liver.
Variability
Significant interindividual variability in CYP2A6 apoprotein and mRNA levels has been observed.
Induction
CYP2A6 is known to be
inducible
Induction, Inducible or Inductive may refer to:
Biology and medicine
* Labor induction (birth/pregnancy)
* Induction chemotherapy, in medicine
* Induced stem cells, stem cells derived from somatic, reproductive, pluripotent or other cell typ ...
by
phenobarbital
Phenobarbital, also known as phenobarbitone or phenobarb, sold under the brand name Luminal among others, is a medication of the barbiturate type. It is recommended by the World Health Organization (WHO) for the treatment of certain types of ep ...
and
rifampicin
Rifampicin, also known as rifampin, is an ansamycin antibiotic used to treat several types of bacterial infections, including tuberculosis (TB), mycobacterium avium complex, ''Mycobacterium avium'' complex, leprosy, and Legionnaires’ disease. ...
, and it is suspected that other antiepileptic drugs may also have this effect.
CYP2A6 Ligands
See also
*
List of cytochrome P450 modulators
This is a list of cytochrome P450 modulators, or enzyme inhibitor, inhibitors and enzyme inducer, inducers of cytochrome P450 enzymes.
List of Herbal cytochrome P450 Inhibitors and Inducers
In alphabetical order.
See also
* List of steroid ...
References
Further reading
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External links
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