cytochrome P450

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CYP11A1

A gene on chromosome 15q23-q24 that encodes a member of the cytochrome P450 superfamily of enzymes, which catalyse reactions involved in drug metabolism and synthesis of cholesterol, steroids and other lipids. CYP11A1 localises to the mitochondrial inner membrane and catalyses the conversion of cholesterol to pregnenolone, the first and rate-limiting step in the synthesis of the steroid hormones.

cytochrome P450

Abbreviation: CYP
A group of enzymes present in every type of cell in the body except red blood cells and skeletal muscle cells. They are important in metabolizing substances normally present in the body such as steroids, fat-soluble vitamins, fatty acids, prostaglandins, and alkaloids. The P450 enzymes also detoxify drugs and a great number of environmental pollutants, such as carcinogens present in tobacco smoke and charcoal-broiled meat, polychlorinated biphenyls, and dioxin. Specialized types of cytochrome P450 are involved in the synthesis of nitric oxide.
See also: cytochrome

cytochrome P450

A family of enzymes responsible for the detoxification and elimination of foreign substances including many drugs by hydroxylation and increasing their solubility. The group has been intensively studied because mutations of the cytochrome P450 gene have been found to be associated with a number of diseases including Addison's disease, liver cancer and Parkinson's disease. Cytochrome P450 can also interfere with drug treatment. Selective inhibitors of aromatase-specific cytochrome P450 have been developed to assist in the treatment of breast cancer.
References in periodicals archive ?
A Drug-Drug Interaction Study to Investigate the Effect of Givosiran on the Activity of Five Major Drug Metabolizing CYP450 Enzymes in Subjects with Acute Intermittent Porphyria (AIP) who are Chronic High Excreters (CHE)
Warfarin and caffeine both the drugs were metabolized by CYP450 enzyme system (Nagui et al., 2001).
Drug Interactions: Apremilast exposure was decreased when Otezla was coadministered with rifampin, a strong CYP450 enzyme inducer; loss of Otezla efficacy may occur.
Research studies caution the use of St John's wort when used in conjunction with most pharmaceutical medications due to its effects on cytochrome P450 (CYP450) mixed-oxidase system, various conjugates and transferases, as well as transporter proteins that modulate drug efflux across intestinal, renal and biliary epithelia.
On the other hand, analysis of these structures showed these compounds are non-substrate for CYP450 2D6, suggesting a moderate metabolism rate of these compounds.
In humans, most DDIs induced by triazoles involve the cytochrome P450 (CYP450) enzymes of the intestinal lumen and liver (25).
Statins are potential substrates for such pathways, but the affinity for specific transporters and CYP450 isoenzymes vary greatly among medications.
However, approximately 5-10% of the drug is metabolized by Cytochrome P450 (CYP450) to a toxic metabolite, N-acetyl-p-benzoquinoneimine (NAPQI).
The genetic predisposition is considered to be mediated by mutations in the CYP450 and CY450-1A3 pharmacokinetic enzymes (2, 16).
VPA is metabolized mainly by the liver via glucuronic acid conjugation and CYP450 beta- and omega-oxidation.