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| (ei näidata 4 kasutaja 4 vahepealset redaktsiooni) |
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| | '''Vitamiin B<sub>6</sub>''' ehk '''püridoksiin''' on vesilahustuv [[vitamiinid|vitamiin]] ja kuulub B-vitamiinide kompleksi. Aktiivseks vormiks on püridoksaalfosfaat (PLP), mis osaleb aminohapete ja süsivesikute ainevahetuses. | | '''Vitamiin B<sub>6</sub>''' ehk '''püridoksiin''' on vesilahustuv [[vitamiinid|vitamiin]] ja kuulub B-vitamiinide kompleksi. Aktiivseks vormiks on püridoksaalfosfaat (PLP), mis osaleb aminohapete ja süsivesikute ainevahetuses. |
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| − | 8vQnTT <a href="http://snsvrjzzvief.com/">snsvrjzzvief</a>, [url=http://keowrqdwcyla.com/]keowrqdwcyla[/url], [link=http://nccfllnguofh.com/]nccfllnguofh[/link], http://vwcphnnqpplz.com/
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| − | ==Funktsioonid==
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| − | Vitamiin B<sub>6</sub> metaboolselt aktiivne vorm püridoksaalfosfaat osaleb makrotoitainete metabolismis, neurotransmitterite, histamiini ja hemoglobiini sünteesis. Pyridoxal phosphate generally serves as a coenzyme for many reactions and can help facilitate decarboxylation, transamination, racemization, elimination, replacement and beta-group interconversion reactions. The liver is the site for vitamin B6 metabolism.
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| − | The primary role of vitamin B<sub>6</sub> is to act as a coenzyme to many other enzymes in the body that are involved predominantly in metabolism. This role is performed by the active form, pyridoxal phosphate. This active form is converted from the two other natural forms founds in food: pyridoxal, pyridoxine and pyridoxamine.
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| − | Vitamin B<sub>6</sub> is involved in the following metabolic processes:
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| − | * amino acid, glucose and lipid metabolism
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| − | * neurotransmitter synthesis
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| − | * histamine synthesis
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| − | * hemoglobin synthesis and function
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| − | * gene expression
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| − | ===Amino Acid Metabolism===
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| − | Pyridoxal phosphate (PLP) is a cofactor in transaminases that can catabolize amino acids. PLP is also an essential component of two enzymes that converts [[methionine]] to [[cysteine]] via two reactions. Low vitamin B<sub>6</sub> status will result in decreased activity of these enzymes. PLP is also an essential cofactor for enzymes involved in the metabolism of [[selenomethionine]] to [[selenohomocysteine]] and then from selenohomocysteine to [[hydrogen selenide]]. Vitamin B<sub>6</sub> is also required for the conversion of [[tryptophan]] to [[niacin]] and low vitamin B<sub>6</sub> status will impair this conversion. PLP is also used to create physiologically active amines by decarboxylation of amino acids. Some notable examples of this include: [[histidine]] to [[histamine]], [[tryptophan]] to [[serotonin]], [[glutamate]] to [[GABA]] ([[gamma-aminobutyric acid]]), and [[dihydroxyphenylalanine]] to [[dopamine]].
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| − | Pyridoxal phosphate is involved in almost all amino acid metabolism, from synthesis to breakdown.
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| − | 1. Transamination: transaminase enzymes needed to break down amino acids are dependent on the presence of pyridoxal phosphate. The proper activity of these enzymes are crucial for the process of moving amine groups from one amino acid to another.
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| − | 2. Transsulfuration: Pyridoxal phosphate is a coenzyme needed for the proper function of the enzymes cystathionine synthase and cystathionase. These enzymes work to transform methionine into cysteine.
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| − | 3. Selenoamino acid metabolism: Selenomethionine is the primary dietary form of selenium. Pyridoxal phosphate is needed as a cofactor for the enzymes that allow selenium to be used from the dietary form. Pyridoxal phosphate also plays a cofactor role in releasing selenium from selenohomocysteine to produce hydrogen selenide. This hydrogen selenide can then be used to incorporate selenium into selenoproteins.
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| − | 4. Vitamin B<sub>6</sub> is also required for the conversion of tryptophan to niacin and low vitamin B<sub>6</sub> status will impair this conversion.
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| − | ==Manustamine sportlastel==
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| − | RDA:
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| − | * '''vastupidavusalad''' 2-6 mg
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| − | * '''jõuspordialad''' 4-12 mg
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| | ==Vaata ka== | | ==Vaata ka== |
