Folates
Mostrando 13-24 de 70 artigos, teses e dissertações.
-
13. Analysis and characterization of the folates in the nonmethanogenic archaebacteria.
A detailed analysis of the folate coenzymes in the nonmethanogenic archaebacteria has been performed. By using the Lactobacillus casei microbiological assay for folates, the levels of folates in Sulfolobus solfataricus and Sulfolobus acidocaldarius were found to be 3.7 and 8.3 ng/g (dry weight) of cells, respectively, compared with 88,000 and 28,000 ng/g (dr
-
14. Structures of the modified folates in the extremely thermophilic archaebacterium Thermococcus litoralis.
The chemical structures of the two modified folates present in Thermococcus litoralis were established. These compounds, each containing a core structure of 1-[4-[[1-(2-amino-7-methyl- 4-oxo-6-pteridinyl)-ethyl]amino]phenyl]-1-deoxy-[1-alpha-D- ribofuranosyl]-ribitol, were characterized. The five position of the ribose in this core structure was beta-linked
-
15. Folates in human serum
Constituent serum folates have been shown to be altered and in some cases raised in diseases in which total folate levels are known to be frequently decreased. Absorption experiments showed that orally administered folate analogues affect the folate pool in different ways. The stability of the 10-formyltetrahydrofolate level in normal subjects is demonstrate
-
16. Enhancement of folates in plants through metabolic engineering
Humans depend on plants as a major source of dietary folates. Inadequate dietary levels of the vitamin folate can lead to megaloblastic anemia, birth defects, impaired cognitive development, and increased risk of cardiovascular disease and cancer. The biofortification of folate levels in food crops is a target for metabolic engineering. Folates are synthesiz
National Academy of Sciences.
-
17. The application of tetrazolium bioautography to the identification of folic acid derivatives
Tetrazolium bioautography has been applied to the identification of folates in solutions of known concentration, and satisfactory resolution has been obtained between pteroyl-L-monoglutamic acid, calcium leucovorin, and N-5-methyltetrahydrofolic acid. The technique is suitable for the identification of folates in biological solutions, and is more specific th
-
18. Acquisition and synthesis of folates by obligate intracellular bacteria of the genus Chlamydia.
We undertook studies focused on folate acquisition by Chlamydia trachomatis L2, Chlamydia psittaci 6BC, and C. psittaci francis. Results from in situ studies, using wild-type host cells, confirmed that C. trachomatis L2 and C. psittaci 6BC are sensitive to sulfonamides whereas C. psittaci francis is resistant. In addition C. trachomatis L2 and C. psittaci fr
-
19. Interaction of methotrexate, folates, and pyridine nucleotides with dihydrofolate reductase: calorimetric and spectroscopic binding studies.
The thermodynamic parameters, deltaG, deltaH, and deltaS characterizing the tight binding of methotrexate, folates, and pyridine nucleotides to chicken liver dihydrofolate reductase (5,6,7,8-tetrahydrofolate: NADP+ oxidoreductase, EC 1.5.1.3) have been determined from calorimetric and fluorescence measurements. At 25 degrees the binding of NADPH and NADP+ is
-
20. Regulation of folylpoly-gamma-glutamate synthesis in bacteria: in vivo and in vitro synthesis of pteroylpoly-gamma-glutamates by Lactobacillus casei and Streptococcus faecalis.
Lactobacillus casei and Streptococcus faecalis accumulated labeled folic acid and metabolized this compound to poly-gamma-glutamates of chain lengths of up to 11 and 5, respectively. Octa- and nonaglutamates predominated in L. casei, and tetraglutamates predominated in S. faecalis. The most effective monoglutamate substrates for the L. casei and S. faecalis
-
21. A common mutation in the methylenetetrahydrofolate reductase gene is associated with an accumulation of formylated tetrahydrofolates in red blood cells
A common mutation (C677T) in the gene encoding for methylenetetrahydrofolate reductase (MTHFR) (5-methyltetrahydrofolate:(acceptor) oxidoreductase, EC 1.7.99.5), a key regulatory enzyme in one-carbon metabolism, results in a thermolabile variant of the MTHFR enzyme with reduced activity in vitro. In the present study we used a chromatographic method for fola
The National Academy of Sciences.
-
22. Total Synthesis of Acetate from CO2: Methyltetrahydrofolate, an Intermediate, and a Procedure for Separation of the Folates
Whole-cell preparations of Clostridium thermoaceticum were exposed to a short pulse of 14CO2 under conditions in which double-labeled acetate was synthesized. Radioactive methyltetrahydrofolate monoglutamate, diglutamate, and triglutamates were isolated from extracts of the cells. The radioactivity was found to be exclusively in the five methyl position. The
-
23. Jejunal Perfusion of Simple and Conjugated Folates in Tropical Sprue
Absorption of labeled simple 3′,5′,9′-3H pteroylmonoglutamate, ([3H]PG-1) and conjugated pteroyl-μ[14C]glutamyl-γ-hexaglutamate, ([14C]PG-7) folates was assessed in six patients with tropical sprue, before and after 6 mo of treatment, utilizing jejunal perfusion and urinary recovery techniques. Degradation products of [14C]PG-7 which were produced du
-
24. Determination of the active portion of the folic acid molecule in cellular slime mold chemotaxis.
From earlier work it is known that folic acid attracts the amoebae of various species of cellular slime molds (11). Here we have tested a wide variety of pteridines, pyrimidines, and pyrazines to determine what part of the folic acid molecule is chemotactically active. It was shown that the activity lies in the pteridine ring itself. Furthermore, the cell-fr