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Pterin
Pterin is a heterocyclic compound composed of a pteridine ring system, with a "keto group" (a lactam) and an amino group on positions 4 and 2 respectively. It is structurally related to the parent bicyclic heterocycle called pteridine. Pterins, as a group, are compounds related to pterin with additional substituents. Pterin itself is of no biological significance. Pterins were first discovered in the pigments of butterfly wings (hence the origin of their name, from the Greek ''pteron (πτερόν)'', wing) and perform many roles in coloration in the biological world. Chemistry Pterins exhibit a wide range of tautomerism in water, beyond what is assumed by just keto-enol tautomerism. For the unsubstituted pterin, at least five tautomers are commonly cited. For 6-methylpterin, seven tautomers are theoretically predicted to be important in solution. The pteridine ring system contains four nitrogen atoms, reducing its aromaticity to the point that it can be attacked by nucleo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dihydropteroate Synthetase
Dihydropteroate synthase is an enzyme classified under . It produces dihydropteroate in bacteria, but it is not expressed in most eukaryotes including humans. This makes it a useful target for sulfonamide antibiotics, which compete with the PABA precursor. * (2-amino-4-hydroxy-7,8-dihydropteridin-6-yl)methyl diphosphate + 4-aminobenzoate (PABA) \rightleftharpoons diphosphate + dihydropteroate. All organisms require reduced folate cofactors for the synthesis of a variety of metabolites. Most microorganisms must synthesize folate de novo because they lack the active transport system of higher vertebrate cells that allows these organisms to use dietary folates. Proteins containing this domain include dihydropteroate synthase () as well as a group of methyltransferase enzymes including methyltetrahydrofolate, corrinoid iron-sulphur protein methyltransferase (MeTr) that catalyses a key step in the Wood-Ljungdahl pathway of carbon dioxide fixation. Dihydropteroate synthase () (D ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Molybdopterin
Molybdopterins are a class of cofactors found in most molybdenum-containing and all tungsten-containing enzymes. Synonyms for molybdopterin are: MPT and pyranopterin-dithiolate. The nomenclature for this biomolecule can be confusing: Molybdopterin itself contains no molybdenum; rather, this is the name of the ligand (a ''pterin'') that will bind the active metal. After molybdopterin is eventually complexed with molybdenum, the complete ligand is usually called molybdenum cofactor. Molybdopterin consists of a pyranopterin, a complex heterocycle featuring a pyran fused to a pterin ring. In addition, the pyran ring features two thiolates, which serve as ligands in molybdo- and tungstoenzymes. In some cases, the alkyl phosphate group is replaced by an alkyl diphosphate nucleotide. Enzymes that contain the molybdopterin cofactor include xanthine oxidase, DMSO reductase, sulfite oxidase, and nitrate reductase. The only molybdenum-containing enzymes that do not feature molybdopteri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pteridine
Pteridine is an aromatic chemical compound composed of fused pyrimidine and pyrazine rings. A pteridine is also a group of heterocyclic compounds containing a wide variety of substitutions on this structure. Pterins and flavins are classes of substituted pteridines that have diverse biological roles. See also * Dihydrobiopterin * Pyrazine * Pyrimidine * Tetrahydrobiopterin Tetrahydrobiopterin (BH4, THB), also known as sapropterin (INN), is a cofactor of the three aromatic amino acid hydroxylase enzymes, used in the degradation of amino acid phenylalanine and in the biosynthesis of the neurotransmitters serotonin ... References {{heterocyclic-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Folate
Folate, also known as vitamin B9 and folacin, is one of the B vitamins. Manufactured folic acid, which is converted into folate by the body, is used as a dietary supplement and in food fortification as it is more stable during processing and storage. Folate is required for the body to make DNA and RNA and metabolise amino acids necessary for cell division. As humans cannot make folate, it is required in the diet, making it an essential nutrient. It occurs naturally in many foods. The recommended adult daily intake of folate in the U.S. is 400 micrograms from foods or dietary supplements. Folate in the form of folic acid is used to treat anemia caused by folate deficiency. Folic acid is also used as a supplement by women during pregnancy to reduce the risk of neural tube defects (NTDs) in the baby. Low levels in early pregnancy are believed to be the cause of more than half of babies born with NTDs. More than 80 countries use either mandatory or voluntary fortification of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Homocysteine
Homocysteine is a non-proteinogenic α-amino acid. It is a homologue of the amino acid cysteine, differing by an additional methylene bridge (-CH2-). It is biosynthesized from methionine by the removal of its terminal Cε methyl group. In the body, homocysteine can be recycled into methionine or converted into cysteine with the aid of certain B-vitamins. High levels of homocysteine in the blood (hyperhomocysteinemia) is regarded as a marker of cardiovascular disease, likely working through atherogenesis, which can result in ischemic injury. Therefore, hyperhomocysteinemia is a possible risk factor for coronary artery disease. Coronary artery disease occurs when an atherosclerotic plaque blocks blood flow to the coronary arteries, which supply the heart with oxygenated blood. Hyperhomocysteinemia has been correlated with the occurrence of blood clots, heart attacks, and strokes, although it is unclear whether hyperhomocysteinemia is an independent risk factor for these conditi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moco Biosynthetic Pathway
Moco may refer to: Biochemistry * Molybdenum cofactor, any of a number of biochemical cofactors * MOCOS, molybdenum cofactor sulfurase * Moco RNA motif, a conserved RNA structure presumed to be a riboswitch that binds molybdenum cofactor * Moco-II RNA motif, a conserved RNA structure identified by bioinformatics Business * Moelis & Company, a global independent investment bank (referred to colloquially as MoCo) * Mozilla Corporation * Nissan Moco, marketed name for the Suzuki MR Wagon in Japan Geography *Montgomery County, Maryland, nicknamed "MoCo" *Mount Moco, the tallest mountain in Angola People * Chilala Moco (born 1977), an Angolan photographer * Marcolino Moco (born 1953), the Prime Minister of Angola 1992–1996 * Didi Mocó, stage name of Brazilian comedian Renato Aragão (born 1935) * Miss Moço, Canadian drag queen * "Moco", stage name of Julian Villarreal from the Mexican band and record producer (Celso Piña) (Banda Machos) (Tigrillos) El Gran Silencio * Moco, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfonamide (medicine)
Sulfonamide is a functional group (a part of a molecule) that is the basis of several groups of drugs, which are called sulphonamides, sulfa drugs or sulpha drugs. The original antibacterial sulfonamides are synthetic (nonantibiotic) antimicrobial agents that contain the sulfonamide group. Some sulfonamides are also devoid of antibacterial activity, e.g., the anticonvulsant sultiame. The sulfonylureas and thiazide diuretics are newer drug groups based upon the antibacterial sulfonamides. Allergies to sulfonamides are common. The overall incidence of adverse drug reactions to sulfa antibiotics is approximately 3%, close to penicillin; hence medications containing sulfonamides are prescribed carefully. Sulfonamide drugs were the first broadly effective antibacterials to be used systemically, and paved the way for the antibiotic revolution in medicine. Function In bacteria, antibacterial sulfonamides act as competitive inhibitors of the enzyme dihydropteroate synthase (DHP ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
4-aminobenzoic Acid
4-Aminobenzoic acid (also known as ''para''-aminobenzoic acid or PABA because the two functional groups are attached to the benzene ring across from one another in the ''para'' position) is an organic compound with the formula H2NC6H4CO2H. PABA is a white solid, although commercial samples can appear gray. It is slightly soluble in water. It consists of a benzene ring substituted with amino and carboxyl groups. The compound occurs extensively in the natural world. Production and occurrence In industry, PABA is prepared mainly by two routes: * Reduction of 4-nitrobenzoic acid * Hoffman degradation of the monoamide derived from terephthalic acid. Food sources of PABA include liver, brewer's yeast (and unfiltered beer), kidney, molasses, mushrooms, and whole grains. A review on this compound. Biology Biochemistry PABA is an intermediate in the synthesis of folate by bacteria, plants, and fungi. Many bacteria, including those found in the human intestinal tract such as ''E ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dihydrofolic Acid
Dihydrofolic acid (conjugate base dihydrofolate) (DHF) is a folic acid ( vitamin B9) derivative which is converted to tetrahydrofolic acid by dihydrofolate reductase. Since tetrahydrofolate is needed to make both purines and pyrimidines, which are building blocks of DNA and RNA, dihydrofolate reductase is targeted by various drugs to prevent nucleic acid Nucleic acids are biopolymers, macromolecules, essential to all known forms of life. They are composed of nucleotides, which are the monomers made of three components: a 5-carbon sugar, a phosphate group and a nitrogenous base. The two main cl ... synthesis. Interactive pathway map Further reading * References Folates {{organic-compound-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrimidine
Pyrimidine (; ) is an aromatic, heterocyclic, organic compound similar to pyridine (). One of the three diazines (six-membered heterocyclics with two nitrogen atoms in the ring), it has nitrogen atoms at positions 1 and 3 in the ring. The other diazines are pyrazine (nitrogen atoms at the 1 and 4 positions) and pyridazine (nitrogen atoms at the 1 and 2 positions). In nucleic acids, three types of nucleobases are pyrimidine derivatives: cytosine (C), thymine (T), and uracil (U). Occurrence and history The pyrimidine ring system has wide occurrence in nature as substituted and ring fused compounds and derivatives, including the nucleotides cytosine, thymine and uracil, thiamine (vitamin B1) and alloxan. It is also found in many synthetic compounds such as barbiturates and the HIV drug, zidovudine. Although pyrimidine derivatives such as alloxan were known in the early 19th century, a laboratory synthesis of a pyrimidine was not carried out until 1879, when Grimaux reported the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Purine
Purine is a heterocyclic compound, heterocyclic aromatic organic compound that consists of two rings (pyrimidine and imidazole) fused together. It is water-soluble. Purine also gives its name to the wider class of molecules, purines, which include substituted purines and their tautomers. They are the most widely occurring nitrogen-containing heterocycles in nature. Dietary sources Purines are found in high concentration in meat and meat products, especially internal organs such as liver and kidney. In general, plant-based diets are low in purines. High-purine plants and algae include some legumes (lentils and Black-eyed pea, black eye peas) and Spirulina (dietary supplement), spirulina. Examples of high-purine sources include: sweetbreads, Anchovies as food, anchovies, Sardines as food, sardines, liver, beef kidneys, Brain as food, brains, meat extracts (e.g., Oxo (food), Oxo, Bovril), herring, mackerel, scallops, game meats, yeast (beer, yeast extract, nutritional yeast) and g ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
TRNA
Transfer RNA (abbreviated tRNA and formerly referred to as sRNA, for soluble RNA) is an adaptor molecule composed of RNA, typically 76 to 90 nucleotides in length (in eukaryotes), that serves as the physical link between the mRNA and the amino acid sequence of proteins. tRNAs genes from Bacteria are typically shorter (mean = 77.6 bp) than tRNAs from Archaea (mean = 83.1 bp) and eukaryotes (mean = 84.7 bp). The mature tRNA follows an opposite pattern with tRNAs from Bacteria being usually longer (median = 77.6 nt) than tRNAs from Archaea (median = 76.8 nt), with eukaryotes exhibiting the shortest mature tRNAs (median = 74.5 nt). Transfer RNA (tRNA) does this by carrying an amino acid to the protein synthesizing machinery of a cell called the ribosome. Complementation of a 3-nucleotide codon in a messenger RNA (mRNA) by a 3-nucleotide anticodon of the tRNA results in protein synthesis based on the mRNA code. As such, tRNAs are a necessary component of translation, the biological ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
