Target type: biologicalprocess
The chemical reactions and pathways resulting in the breakdown of phylloquinone, vitamin K1, a quinone-derived compound synthesized by green plants. [GOC:jl, http://www.dentistry.leeds.ac.uk/biochem/thcme/vitamins.html#k]
Phylloquinone, also known as vitamin K1, is a vital cofactor for various carboxylase enzymes involved in blood clotting and bone metabolism. Its catabolic process is crucial for maintaining homeostasis and preventing excessive accumulation.
The initial step involves the hydroxylation of the phylloquinone molecule at the 2-position, catalyzed by cytochrome P450 enzymes, specifically CYP3A4 in humans. This hydroxylation reaction transforms phylloquinone into 2-hydroxyphylloquinone.
Subsequently, 2-hydroxyphylloquinone undergoes further oxidation to form 2,3-epoxyphylloquinone. This oxidation step is mediated by epoxide hydrolases, a family of enzymes that catalyze the hydrolysis of epoxides.
The resulting 2,3-epoxyphylloquinone is then converted to phylloquinone-2,3-epoxide by epoxide reductase enzymes. These enzymes play a critical role in the detoxification of epoxides, including those derived from phylloquinone.
The final stage of phylloquinone catabolism involves the conjugation of phylloquinone-2,3-epoxide with glucuronic acid, forming a water-soluble conjugate. This conjugation process is catalyzed by UDP-glucuronosyltransferases, a family of enzymes responsible for the detoxification and excretion of various xenobiotics and endogenous compounds.
The glucuronidated phylloquinone-2,3-epoxide is then readily excreted from the body via bile and urine.
The catabolic process of phylloquinone ensures its effective elimination from the body, preventing its potential accumulation and toxic effects. It also plays a role in regulating the levels of vitamin K1, ensuring its availability for essential metabolic functions.'
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| 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) |
| 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 |