Folate 1-carbon metabolism

Connections To folate metabolism and one-carbon metabolism in de novo synthesis. 

APPLING, D.R., Compartmentation of folate-mediated one-carbon metabolism in eukaryotes, FASEB J., 1991, 5, 2645-2651. 

COSSINS, E.A., CHEN, L., Folates and one-carbon metabolism in plants and fungi, Phytochemistry, 1997, 45, 437-452. 

BALAGHI, M., HORNE, D.W., WAGNER, C., Hepatic one-carbon metabolism in early folate-deficiency in rats, Biochem. J., 1993,291,145-149. 

Biotin metabolism Folate biosynthesis One carbon pool by folate Retinol metabolism Porphyrin and chlorophyll metabolism Terpenoid biosynthesis Xenobiotics metabolism Ubiquinone biosynthesis Flavonoids, stilbene, and lignin biosynthesis... 

Folic acid (or folate), which plays a key role in one-carbon metabolism, is essential for the biosynthesis of several compounds. Folic acid deficiency is probably the most common vitamin deficiency in the United States, particularly among pregnant women and alcoholics. 

Involvement of folate coenzymes in one-carbon metabolism. Shown in red are the one-carbon units of the end products that originate with the reactive one-carbon units of the folate coenzymes. 

The possible relationship of the methane fermentation with the more conventional examples of one-carbon metabolism as catalyzed by folate and vitamin B12 cofactors has been long apparent. 5-Methyl tetrahydro-folate, 5,10-methylene tetrahydrofolate, and methyl vitamin B12 are converted to methane by cell-free extracts of M. barkeri 32) and M. omeli-anskii (33). The involvement of vitamin B12 is further implicated by its high cellular level in methane bacteria and by the isolation of B12-containing proteins in extracts of M. barkeri 30) which stimulate methane evolution from methyl vitamin B12. The components and pathways that can be demonstrated in cell-free M. barkeri extracts 32) are listed below. 

The histidine load test is not used in the clinical setting and is only sometimes used by researchers however, a description of this test provides a clear-cut example of how folates behave in the mediation of 1-carbon metabolism. Histidine catabolism takes place in the liver according to the pathway sho vn (Figures 9.16 and 9.17). The intermediates, formiminoglulamic acid and j-forrnirnino-H folate, bear the formimino group —CH hJH. 

Serine hydroxymethyltransferase Production of one-carbon units for use in folate-mediated metabolism... 

Folate coenzymes, together with coenzymes derived from vitamins B12, Bg, and B2, are essential for one-carbon metabolism. Biochemically, a carbon unit from serine or glycine is... 

In summary, folate is a vitamin acquired from the diet that is essential for 1-carbon metabolism. Inadequate folate levels inhibit DNA synthesis by limiting purine nucleotide and dTMP levels, which results in the abnormal cellular proliferation observed in megaloblastic anemia. Folate is also required to replenish the methionine pool for SAM-dependent methylation reactions. 

Folic acid (Mr = 441, Fig. 1) is a vitamin essential for de novo nucleotide synthesis and one-carbon metabolism. The ability to acquire folate, therefore, is important to the viability of proliferating cells. 

V. Schirch, Mechanism of Folate-Requiring Enzymes in One-Carbon Metabolism) Academic Press San Diego, 1998 Vol. 2, pp 211-252. 

Question Are all the above folate compounds involved in one-carbon metabolism ... 

Kim, J.-S., Lowe, K. E., and Shane, B. (1993). Regulation of folate and one carbon metabolism in mammalian cells. 4. Role of folylpolyglutamate synthetase in antifolate metabolism and cytotoxicity. J. Biol. Chem. 268, 21 0-21685. 

Selhub, J., 2002. Folate, vitamin B12 and vitamin B6 and one carbon metabolism. Journal of Nutrition, Health and Aging. 6 39-42. 

Folate, a water-soluble B vitamin, is important in one-carbon metabolism. It plays a key role in amino acid metabolism and is important for the synthesis of DNA, some neurotransmittors and myelin, which is essential for the function of neurons. In utero, there is active transport of folate from mother to baby and, therefore, deficiency is seldom observed in newborns. 

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