Abstract
In an aseptic microbiological assay of folate compounds and their breakdown compounds, using Lactobacillus casei, Streptococcus faecalis, and Pediococcus cerevisiae, 4a-hydroxy-5methyl-4,5,6,7-tetrahydrofolate and 5-methyl-5,8-dihydrofolate were inactive under all conditions to all three organisms and 5-methyl-5,6-dihydrofolate was inactive unless ascorbate was present in the incubation medium, and then only to L. casei. 5-Methyltetrahydrofolate was active only for L. casei, and activity in purified samples to S. faecalis was due to trace amounts of folic acid. Analysis of S. faecalis values in the serum in normal subjects and in patients with various disorders showed that levels of 10-formyltetrahydrofolate are raised in coeliac disease, leukaemia, rheumatoid arthritis, and schizophrenia. 5-Methyltetrahydrofolate is readily absorbed by normal human subjects and by patients with pernicious anaemia but poorly absorbed by patients with coeliac disease or leukaemia. 5-Methyl-5,6-dihydrofolate was quickly absorbed by normal human subjects, being reflected by a considerably raised level of 5-methyltetrahydrofolate in serum when sodium bicarbonate was given by mouth before the 5-methyl-5,6-dihydrofolate. These higher levels were comparable to those in patients with pernicious anaemia after oral administration of 5-methyl-5,6-dihydrofolate. Oral 5-methyl-5,8-dihydrofolate and 4a-hydroxy-5-methyl-tetrahydrofolate did not appear as microbiologically active folates in the serum. The findings of this study suggest that the availability for biological utilisation of the major dietary folate compounds will depend on the amount of gastric acidity and of ascorbate in the intestinal chyme. Many may be unavailable for metabolic utilization in the body.
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- Benn A., Swan C. H., Cooke W. T., Blair J. A., Matty A. J., Smith M. E. Effect of intraluminal pH on the absorption of pteroylmonoglutamic acid. Br Med J. 1971 Jan 16;1(5741):148–150. doi: 10.1136/bmj.1.5741.148. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Blair J. A., Saunders K. J. A convenient method for the preparation of dl-5-methyltetrahydrofolic acid (dl-5-methyl-5,6,7,8-tetrahydropteroyl-L-monoglutamic acid). Anal Biochem. 1970 Apr;34(2):376–381. doi: 10.1016/0003-2697(70)90122-3. [DOI] [PubMed] [Google Scholar]
- Brown J. P., Davidson G. E., Scott J. M. Thin-layer chromatography of pteroylglutamates and related compounds. Application to transport and metabolism of reduced folates in blood. J Chromatogr. 1973 May 16;79:195–207. doi: 10.1016/s0021-9673(01)85289-4. [DOI] [PubMed] [Google Scholar]
- DONALDSON K. O., KERESZTESY J. C. Naturally occurring forms of folic acid. III. Characterization and properties of 5-methyldihydrofolate, an oxidation product of 5-methyltetrahydrofolate. J Biol Chem. 1962 Dec;237:3815–3819. [PubMed] [Google Scholar]
- DaCosta M., Rothenberg P. Identification of an immunoreactive folate in serum extracts by radioimmunoassay. Br J Haematol. 1971 Jul;21(1):121–130. doi: 10.1111/j.1365-2141.1971.tb03422.x. [DOI] [PubMed] [Google Scholar]
- Gapski G. R., Whiteley J. M., Huennekens F. M. Hydroxylated derivatives of 5-methyl-5,6,7,8-tetrahydrofolate. Biochemistry. 1971 Jul 20;10(15):2930–2934. doi: 10.1021/bi00791a021. [DOI] [PubMed] [Google Scholar]
- Herbert V. Aseptic addition method for Lactobacillus casei assay of folate activity in human serum. J Clin Pathol. 1966 Jan;19(1):12–16. doi: 10.1136/jcp.19.1.12. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Leeming R. J., Portman-Graham H., Swan C. H., Blair J. A. The application of tetrazolium bioautography to the identification of folic acid derivatives. J Clin Pathol. 1970 Jul;23(5):411–413. doi: 10.1136/jcp.23.5.411. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Ratanasthien K., Blair J. A., Leeming R. J., Cooke W. T., Melikian V. Folates in human serum. J Clin Pathol. 1974 Nov;27(11):875–879. doi: 10.1136/jcp.27.11.875. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rosenblatt D. S., Erbe R. W. Reciprocal changes in the levels of functionally related folate enzymes during the culture cycle in human fibroblasts. Biochem Biophys Res Commun. 1973 Oct 15;54(4):1627–1633. doi: 10.1016/0006-291x(73)91173-x. [DOI] [PubMed] [Google Scholar]
- Weir D. G., Brown J. P., Freedman D. S., Scott J. M. The absorption of the diastereoisomers of 5-methyltetrahydropteroylglutamate in man: a carrier-mediated process. Clin Sci Mol Med. 1973 Nov;45(5):625–631. doi: 10.1042/cs0450625. [DOI] [PubMed] [Google Scholar]