alpha-tocopherol omega-hydroxylase activity
Definition
Target type: molecularfunction
Catalysis of the reaction: alpha-tocopherol + O2 + NADPH + H+ = 13'-hydroxy-alpha-tocopherol + NADP+ + H2O . [MetaCyc:RXN-11003]
Alpha-tocopherol omega-hydroxylase (CYP3A4) is a cytochrome P450 enzyme that catalyzes the hydroxylation of alpha-tocopherol, the most abundant form of vitamin E, at the omega position of the phytyl side chain. This reaction is the first step in the catabolism of alpha-tocopherol, leading to its excretion. The enzyme is highly specific for alpha-tocopherol and does not metabolize other tocopherol isomers or other lipid-soluble vitamins. The hydroxylated product, alpha-tocopherol quinone, is then further metabolized to alpha-tocopherol carboxylate, which is excreted in the bile and urine. The exact physiological function of this pathway is not fully understood, but it is thought to be involved in regulating the levels of alpha-tocopherol in the body. CYP3A4 is also known to be involved in the metabolism of a wide variety of drugs, including anti-cancer drugs, antibiotics, and immunosuppressants. The activity of CYP3A4 can be affected by a number of factors, including age, gender, genetic factors, and the presence of other drugs or chemicals. The precise mechanism by which CYP3A4 catalyzes the hydroxylation of alpha-tocopherol is not fully understood, but it is thought to involve a two-electron oxidation reaction. The enzyme utilizes molecular oxygen and NADPH to perform this reaction. The exact mechanism of action and the specific role of CYP3A4 in alpha-tocopherol metabolism remain areas of active research.'
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Proteins (1)
| Protein | Definition | Taxonomy |
|---|---|---|
| Cytochrome P450 4F2 | A cytochrome P450 4F2 that is encoded in the genome of human. [PRO:DNx, UniProtKB:P78329] | Homo sapiens (human) |
Compounds (6)
| Compound | Definition | Classes | Roles |
|---|---|---|---|
| 17-octadecynoic acid | octadec-17-ynoic acid : An acetylenic fatty acid that is octadecanoi acid (stearic acid) which has been doubly dehydrogenated at positions 17 and 18 to give the corresponding alkynoic acid. | acetylenic fatty acid; long-chain fatty acid; monounsaturated fatty acid; terminal acetylenic compound | EC 1.14.14.94 (leukotriene-B4 20-monooxygenase) inhibitor; EC 1.14.15.3 (alkane 1-monooxygenase) inhibitor; P450 inhibitor |
| ketoconazole | 1-acetyl-4-(4-{[2-(2,4-dichlorophenyl)-2-(1H-imidazol-1-ylmethyl)-1,3-dioxolan-4-yl]methoxy}phenyl)piperazine : A dioxolane that is 1,3-dioxolane which is substituted at positions 2, 2, and 4 by imidazol-1-ylmethyl, 2,4-dichlorophenyl, and [para-(4-acetylpiperazin-1-yl)phenoxy]methyl groups, respectively. | dichlorobenzene; dioxolane; ether; imidazoles; N-acylpiperazine; N-arylpiperazine | |
| tranylcypromine | (1R,2S)-tranylcypromine : A 2-phenylcyclopropan-1-amine that is the (1R,2S)-enantiomer of tranylcypromine. tranylcypromine : A racemate comprising equal amounts of (1R,2S)- and (1S,2R)-2-phenylcyclopropan-1-amine. An irreversible monoamine oxidase inhibitor that is used as an antidepressant (INN tranylcypromine). Tranylcypromine: A propylamine formed from the cyclization of the side chain of amphetamine. This monoamine oxidase inhibitor is effective in the treatment of major depression, dysthymic disorder, and atypical depression. It also is useful in panic and phobic disorders. (From AMA Drug Evaluations Annual, 1994, p311) | 2-phenylcyclopropan-1-amine | |
| proadifen hydrochloride | |||
| pirlindole | pirlindole: RN given refers to parent cpd; synonym pyrazidol refers to mono-HCl; structure in Negwer, 5th ed, #2812 | carbazoles | |
| kaf156 | ganaplacide: antimalarial |