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5,10-Methenyltetrahydrofolate
5,10-Methenyltetrahydrofolate (5,10-CH=THF) is a form of tetrahydrofolate that is an intermediate in metabolism. 5,10-CH=THF is a coenzyme that accepts and donates methenyl (CH=) groups. It is produced from 5,10-methylenetetrahydrofolate by either a NAD+ dependent methylenetetrahydrofolate dehydrogenase, or a NADP+ dependent dehydrogenase. It can also be produced as an intermediate in histidine catabolism, by formiminotransferase cyclodeaminase, from 5-formiminotetrahydrofolate. 5,10-CH=THF is a substrate for methenyltetrahydrofolate cyclohydrolase In enzymology, a methenyltetrahydrofolate cyclohydrolase () is an enzyme that catalyzes the chemical reaction :5,10-methenyltetrahydrofolate + H2O \rightleftharpoons 10-formyltetrahydrofolate Thus, the two substrates of this enzyme are 5,10-met ..., which converts it into 10-formyltetrahydrofolate. Interactive pathway map References {{DEFAULTSORT:Methenyltetrahydrofolate, 5,10- Folates Coenzymes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
5,10-methylenetetrahydrofolate
5,10-Methylenetetrahydrofolate (N5,N10-Methylenetetrahydrofolate; 5,10-CH2-THF) is cofactor in several biochemical reactions. It exists in nature as the diastereoisomer R5,10-methylene-THF. As an intermediate in one-carbon metabolism, 5,10-CH2-THF interconverts to 5-methyltetrahydrofolate, 5-formyltetrahydrofolate, and methenyltetrahydrofolate. It is substrate for the enzyme methylenetetrahydrofolate reductase (MTHFR) It is mainly produced by the reaction of tetrahydrofolate with serine, catalyzed by the enzyme serine hydroxymethyltransferase. Selected functions Formaldehyde detoxification Methylenetetrahydrofolate is an intermediate in the detoxification of formaldehyde. Pyrimidine biosynthesis It is the one-carbon donor for thymidylate synthase, for methylation of 2-deoxy-uridine-5-monophosphate ( dUMP) to 2-deoxy-thymidine-5-monophosphate (dTMP). The coenzyme is necessary for the biosynthesis of thymidine and is the C1-donor in the reactions catalyzed by TS and thymidyla ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tetrahydrofolate
Tetrahydrofolic acid (THFA), or tetrahydrofolate, is a folic acid derivative. Metabolism Human synthesis Tetrahydrofolic acid is produced from dihydrofolic acid by dihydrofolate reductase. This reaction is inhibited by methotrexate. It is converted into 5,10-methylenetetrahydrofolate by serine hydroxymethyltransferase. Bacterial synthesis Many bacteria use dihydropteroate synthetase to produce dihydropteroate, a molecule without function in humans. This makes it a useful target for sulfonamide antibiotics, which compete with the PABA precursor. Functions Tetrahydrofolic acid is a cofactor in many reactions, especially in the synthesis (or anabolism) of amino acids and nucleic acids. In addition, it serves as a carrier molecule for single-carbon moieties, that is, groups containing one carbon atom e.g. methyl, methylene, methenyl, formyl, or formimino. When combined with one such single-carbon moiety as in 10-formyltetrahydrofolate, it acts as a donor of a group ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metabolism
Metabolism (, from el, μεταβολή ''metabolē'', "change") is the set of life-sustaining chemical reactions in organisms. The three main functions of metabolism are: the conversion of the energy in food to energy available to run cellular processes; the conversion of food to building blocks for proteins, lipids, nucleic acids, and some carbohydrates; and the elimination of metabolic wastes. These enzyme-catalyzed reactions allow organisms to grow and reproduce, maintain their structures, and respond to their environments. The word metabolism can also refer to the sum of all chemical reactions that occur in living organisms, including digestion and the transportation of substances into and between different cells, in which case the above described set of reactions within the cells is called intermediary (or intermediate) metabolism. Metabolic reactions may be categorized as ''catabolic'' – the ''breaking down'' of compounds (for example, of glucose to pyruvate by ce ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coenzyme
A cofactor is a non-protein chemical compound or metallic ion that is required for an enzyme's role as a catalyst (a catalyst is a substance that increases the rate of a chemical reaction). Cofactors can be considered "helper molecules" that assist in biochemical transformations. The rates at which these happen are characterized in an area of study called enzyme kinetics. Cofactors typically differ from ligands in that they often derive their function by remaining bound. Cofactors can be divided into two types: inorganic ions and complex organic molecules called coenzymes. Coenzymes are mostly derived from vitamins and other organic essential nutrients in small amounts. (Note that some scientists limit the use of the term "cofactor" for inorganic substances; both types are included here.) Coenzymes are further divided into two types. The first is called a "prosthetic group", which consists of a coenzyme that is tightly (or even covalently) and permanently bound to a protein. The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methylenetetrahydrofolate Dehydrogenase (NAD+)
In enzymology, a methylenetetrahydrofolate dehydrogenase (NAD+) () is an enzyme that catalyzes a chemical reaction. :5,10-methylenetetrahydrofolate + NAD+ \rightleftharpoons 5,10-methenyltetrahydrofolate + NADH + H+ Thus, the two substrates of this enzyme are 5,10-methylenetetrahydrofolate and NAD+, whereas its 3 products are 5,10-methenyltetrahydrofolate, NADH, and H+. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-NH group of donors with NAD+ or NADP+ as acceptor. The systematic name of this enzyme class is 5,10-methylenetetrahydrofolate:NAD+ oxidoreductase. This enzyme is also called methylenetetrahydrofolate dehydrogenase (NAD+). This enzyme participates in one carbon pool by folate. Structural studies As of late 2007, two structures A structure is an arrangement and organization of interrelated elements in a material object or system, or the object or system so organized. Material structures include man-made objects such a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methylenetetrahydrofolate Dehydrogenase (NADP+)
In enzymology, a methylenetetrahydrofolate dehydrogenase (NADP+) () is an enzyme that catalyzes the chemical reaction :5,10-methylenetetrahydrofolate + NADP+ \rightleftharpoons 5,10-methenyltetrahydrofolate + NADPH + H+ Thus, the two substrates of this enzyme are 5,10-methylenetetrahydrofolate and NADP+, whereas its 3 products are 5,10-methenyltetrahydrofolate, NADPH, and H+. This enzyme belongs to the family of oxidoreductases, specifically those acting on the CH-NH group of donors with NAD+ or NADP+ as acceptor. This enzyme participates in glyoxylate and dicarboxylate metabolism and one carbon pool by folate. Structural studies As of late 2007, 8 structures have been solved for this class of enzymes, with PDB accession codes , , , , , , , and . Clinical significance Mutations of the MTHFD1 gene may disrupt the activity of the enzyme and cause methylenetetrahydrofolate dehydrogenase 1 deficiency, also known as combined immunodeficiency and megaloblastic anemia with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Histidine
Histidine (symbol His or H) is an essential amino acid that is used in the biosynthesis of proteins. It contains an α-amino group (which is in the protonated –NH3+ form under biological conditions), a carboxylic acid group (which is in the deprotonated –COO− form under biological conditions), and an imidazole side chain (which is partially protonated), classifying it as a positively charged amino acid at physiological pH. Initially thought essential only for infants, it has now been shown in longer-term studies to be essential for adults also. It is encoded by the codons CAU and CAC. Histidine was first isolated by Albrecht Kossel and Sven Gustaf Hedin in 1896. It is also a precursor to histamine, a vital inflammatory agent in immune responses. The acyl radical is histidyl. Properties of the imidazole side chain The conjugate acid (protonated form) of the imidazole side chain in histidine has a p''K''a of approximately 6.0. Thus, below a pH of 6, the imidazole ring ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Formiminotransferase Cyclodeaminase
Formimidoyltransferase cyclodeaminase or formiminotransferase cyclodeaminase (symbol FTCD in humans) is an enzyme that catalyzes the conversion of formiminoglutamate and tetrahydrofolate into formiminotetrahydrofolate and glutamate. Role in pathology Mutations of the FTCD gene cause glutamate formiminotransferase deficiency. See also * Glutamate-1-semialdehyde Glutamate-1-semialdehyde is a molecule formed from by the reduction of tRNA bound glutamate, catalyzed by glutamyl-tRNA reductase. It is isomerized by glutamate-1-semialdehyde 2,1-aminomutase to give aminolevulinic acid in the biosynthesis of por ... References External links * {{lyase-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Methenyltetrahydrofolate Cyclohydrolase
In enzymology, a methenyltetrahydrofolate cyclohydrolase () is an enzyme that catalyzes the chemical reaction :5,10-methenyltetrahydrofolate + H2O \rightleftharpoons 10-formyltetrahydrofolate Thus, the two substrates of this enzyme are 5,10-methenyltetrahydrofolate and H2O, whereas its product is 10-formyltetrahydrofolate. This enzyme belongs to the family of hydrolases, those acting on carbon-nitrogen bonds other than peptide bonds, specifically in cyclic amidines. This enzyme participates in glyoxylate and dicarboxylate metabolism and one carbon pool by folate. Synonyms The systematic name of this enzyme class is 5,10-methenyltetrahydrofolate 5-hydrolase (decyclizing). Other names in common use include: * Citrovorum factor cyclodehydrase * cyclohydrolase * formyl-methenyl-methylenetetrahydrofolate synthetase (combined). Structural studies As of late 2007, 6 structures A structure is an arrangement and organization of interrelated elements in a material object or syst ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
