Posted by raybakes on October 24, 2004, at 14:22:01
In reply to Folic/Folinic acid,P5P,glutamine,betaine,methionin » raybakes, posted by tealady on October 23, 2004, at 19:57:48
>
> ****And it begins to come together....tada!****
>
> "In plants, FOLIC ACID is formed from a hetero-bicyclic pteride ring, paraaminobenzoic acid (PABA), and GLUTAMIC ACID (see Figure 2).
> FOLATE is initially deconjugated in the cells of the intestinal wall to the MONOGLUTAMATE form. This is then reduced to dihydrofolate and then to tetrahydrofolate (THF) via folate and dihydrofolate reductase."
>
> Both of these enzymes require NADPH (niacin dependent) as a cofactor.
> Serine combines with pyridoxal-5'-phosphate(P5P B6) to transfer a hydroxymethyl group to THF. This results in the formation of 5, 10-methylenetetrahydrofolate (methylene THF) and glycine. (see Figure 3) This molecule is of central importance, being the precursor of the metabolically-active 5- ethyltetrahydrofolate (5-methylTHF, which is involved in homocysteine metabolism) and methy-lidynetetrahydrofolate (involved in purine synthesis), as well as functioning on its own in the generation of THYMINE side chains for incorporation into DNA.
>
> Enzyme or cofactor deficiency needed for generation of active folic acid.
> Folinic acid (5-formylTHF- available supplementally as calcium folinate—also known as leucovorin calcium) is an immediate precursor to 5, 10 methyleneTHF and 5- methylTHF. Folinic acid is more stable than folic acid and has a longer half-life in the body.
> Folinic acid also readily crosses the bloodbrain barrier and is slowly cleared, compared to folic acid, which is poorly transported into the brain, and once in the CNS is rapidly cleared.15
>
>
> so we have the betaine,
> folic acid, glutamine(glutamic acid used in folate canversion)/glutamate ( monoglutamate form of folic acid),
> NADPH( both enzymes require NADPH (niacin dependent) as a cofactor),
> generation of thymine side chains
> pyridoxal-5'-phosphate
> methionine
>
> "Betaine supplementation has been shown to reduce homocysteine levels while resulting in modest increases of plasma serine and simultaneous increases of plasma cysteine levels.7 Serine levels are depressed in some individuals with excess homocysteine who are treated with folic acid, cobalamin, and vitamin B6"
>
> "Because serine is required for:
> 1)the conversion of folic acid to its active form,
> 2) as a shuttle for methyl groups between the cytosol and the mitochondria, and
> 3) as a cofactor in the trans-sulfuration pathway of methionine/ homocysteine metabolism"
>
> "Folinic acid also readily crosses the bloodbrain barrier and is slowly cleared, compared to folic acid, which is poorly transported into the brain, and once in the CNS is rapidly cleared."
>
> http://www.thorne.com/pdf/journal/1-4/homocysteinemetabolism.pdf
>
>
>
>Well done Jan, that's a brilliant article! Interesting the bit about SAM being needed for CoQ10 manufacture too - I wonder whether a CoQ10 supplement needs to be remethylated after a while, and if it can raise homocyteine?
Ray
poster:raybakes
thread:359642
URL: http://www.dr-bob.org/babble/alter/20041022/msgs/406664.html