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Deoxyuridine Phosphorylase
In enzymology, a deoxyuridine phosphorylase is an enzyme that catalyzes the chemical reaction :2'-deoxyuridine + phosphate \rightleftharpoons uracil + 2-deoxy-alpha-D-ribose 1-phosphate Thus, the two substrates of this enzyme are 2'-deoxyuridine and phosphate, whereas its two products are uracil and 2-deoxy-alpha-D-ribose 1-phosphate. No enzyme is known to be specific for this reaction, hence the EC number originally assigned to this enzyme function (EC 2.4.2.23) was deleted by the IUBMB in 2013. The reaction is catalysed by , pyrimidine-nucleoside phosphorylase, , uridine phosphorylase, and , thymidine phosphorylase. These enzymes belong to the family of glycosyltransferases, specifically the pentosyltransferases. They participate in pyrimidine metabolism Pyrimidine biosynthesis occurs both in the body and through organic synthesis. ''De novo'' biosynthesis of pyrimidine ''De Novo'' biosynthesis of a pyrimidine is catalyzed by three gene products CAD, DHODH and UMP ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzymology
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. Almost all metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called ''enzymology'' and the field of pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Other biocatalysts are catalytic RNA molecules, called ribozymes. Enzymes' specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the reaction ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme Commission Number
The Enzyme Commission number (EC number) is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. As a system of enzyme nomenclature, every EC number is associated with a recommended name for the corresponding enzyme-catalyzed reaction. EC numbers do not specify enzymes but enzyme-catalyzed reactions. If different enzymes (for instance from different organisms) catalyze the same reaction, then they receive the same EC number. Furthermore, through convergent evolution, completely different protein folds can catalyze an identical reaction (these are sometimes called non-homologous isofunctional enzymes) and therefore would be assigned the same EC number. By contrast, UniProt identifiers uniquely specify a protein by its amino acid sequence. Format of number Every enzyme code consists of the letters "EC" followed by four numbers separated by periods. Those numbers represent a progressively finer classification of the enzyme. Preliminary EC ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrimidine Metabolism
Pyrimidine biosynthesis occurs both in the body and through organic synthesis. ''De novo'' biosynthesis of pyrimidine ''De Novo'' biosynthesis of a pyrimidine is catalyzed by three gene products CAD, DHODH and UMPS. The first three enzymes of the process are all coded by the same gene in CAD which consists of carbamoyl phosphate synthetase II, aspartate carbamoyltransferase and dihydroorotase. Dihydroorotate dehydrogenase (DHODH) unlike CAD and UMPS is a mono-functional enzyme and is localized in the mitochondria. UMPS is a bifunctional enzyme consisting of orotate phosphoribosyltransferase (OPRT) and orotidine monophosphate decarboxylase (OMPDC). Both, CAD and UMPS are localized around the mitochondria, in the cytosol. In Fungi, a similar protein exists but lacks the dihydroorotase function: another protein catalyzes the second step. In other organisms (Bacteria, Archaea and the other Eukaryota), the first three steps are done by three different enzymes. Pyrimidine cata ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glycosyltransferase
Glycosyltransferases (GTFs, Gtfs) are enzymes ( EC 2.4) that establish natural glycosidic linkages. They catalyze the transfer of saccharide moieties from an activated nucleotide sugar (also known as the "glycosyl donor") to a nucleophilic glycosyl acceptor molecule, the nucleophile of which can be oxygen- carbon-, nitrogen-, or sulfur-based. The result of glycosyl transfer can be a carbohydrate, glycoside, oligosaccharide, or a polysaccharide. Some glycosyltransferases catalyse transfer to inorganic phosphate or water. Glycosyl transfer can also occur to protein residues, usually to tyrosine, serine, or threonine to give O-linked glycoproteins, or to asparagine to give N-linked glycoproteins. Mannosyl groups may be transferred to tryptophan to generate C-mannosyl tryptophan, which is relatively abundant in eukaryotes. Transferases may also use lipids as an acceptor, forming glycolipids, and even use lipid-linked sugar phosphate donors, such as dolichol phosphates in eukaryotic o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thymidine Phosphorylase
Thymidine phosphorylase () is an enzyme that is encoded by the TYMP (gene), TYMP gene and catalyzes the reaction: :thymidine + phosphate \rightleftharpoons thymine + 2-deoxy-alpha-D-ribose 1-phosphate Thymidine phosphorylase is involved in purine metabolism, pyrimidine metabolism, and other metabolism, metabolic pathways. Variations in thymidine phosphorylase and the ''TYMP'' gene that encode it are associated with Mitochondrial neurogastrointestinal encephalopathy syndrome, mitochondrial neurogastrointestinal encephalopathy (MNGIE) syndrome and bladder cancer. Nomenclature This enzyme belongs to the family of glycosyltransferases, specifically the pentosyltransferases. The List of enzymes, systematic name of this enzyme class is thymidine:phosphate deoxy-alpha-D-ribosyltransferase. Other names in common use include pyrimidine phosphorylase, thymidine-orthophosphate deoxyribosyltransferase, animal growth regulators, blood platelet-derived endothelial cell, growth factors, bl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uridine Phosphorylase
In enzymology, an uridine phosphorylase () is an enzyme that catalyzes the chemical reaction :uridine + phosphate \rightleftharpoons uracil + alpha-D-ribose 1-phosphate Thus, the two substrates of this enzyme are uridine and phosphate, whereas its two products are uracil and alpha-D-ribose 1-phosphate. This enzyme belongs to the family of glycosyltransferases, specifically the pentosyltransferases. The systematic name of this enzyme class is uridine:phosphate alpha-D-ribosyltransferase. Other names in common use include pyrimidine phosphorylase, UrdPase, UPH, and UPase. This enzyme participates in pyrimidine metabolism Pyrimidine biosynthesis occurs both in the body and through organic synthesis. ''De novo'' biosynthesis of pyrimidine ''De Novo'' biosynthesis of a pyrimidine is catalyzed by three gene products CAD, DHODH and UMPS. The first three enzymes of .... Structural studies As of late 2007, 27 structures have been solved for this class of enzymes, with P ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrimidine-nucleoside Phosphorylase
In enzymology, a pyrimidine-nucleoside phosphorylase () is an enzyme that catalyzes the chemical reaction :a pyrimidine nucleoside + phosphate \rightleftharpoons a pyrimidine base + alpha-D-ribose 1-phosphate Thus, the two substrates of this enzyme are pyrimidine nucleoside and phosphate, whereas its two products are pyrimidine base and alpha-D-ribose 1-phosphate. This enzyme belongs to the family of glycosyltransferases, specifically the pentosyltransferases. The systematic name of this enzyme class is pyrimidine-nucleoside:phosphate alpha-D-ribosyltransferase. This enzyme is also called Py-NPase. This enzyme participates in pyrimidine metabolism. 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 as buildings and machines and natural objects such as ... have been solved for this ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IUBMB
The International Union of Biochemistry and Molecular Biology (IUBMB) is an international non-governmental organisation concerned with biochemistry and molecular biology. Formed in 1955 as the International Union of Biochemistry (IUB), the union has presently 79 member countries and regions (as of 2020).IUBMB: the first half-century. /ref> The Union is devoted to promoting research and education in biochemistry and molecular biology throughout the world and gives particular attention to areas where the subject is still in its early development History The first Congress of Biochemistry ...[...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enzyme
Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products. Almost all metabolic processes in the cell need enzyme catalysis in order to occur at rates fast enough to sustain life. Metabolic pathways depend upon enzymes to catalyze individual steps. The study of enzymes is called ''enzymology'' and the field of pseudoenzyme analysis recognizes that during evolution, some enzymes have lost the ability to carry out biological catalysis, which is often reflected in their amino acid sequences and unusual 'pseudocatalytic' properties. Enzymes are known to catalyze more than 5,000 biochemical reaction types. Other biocatalysts are catalytic RNA molecules, called ribozymes. Enzymes' specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the reaction ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uracil
Uracil () (symbol U or Ura) is one of the four nucleobases in the nucleic acid RNA. The others are adenine (A), cytosine (C), and guanine (G). In RNA, uracil binds to adenine via two hydrogen bonds. In DNA, the uracil nucleobase is replaced by thymine (T). Uracil is a demethylated form of thymine. Uracil is a common and naturally occurring pyrimidine derivative. The name "uracil" was coined in 1885 by the German chemist Robert Behrend, who was attempting to synthesize derivatives of uric acid. Originally discovered in 1900 by Alberto Ascoli, it was isolated by hydrolysis of yeast nuclein; it was also found in bovine thymus and spleen, herring sperm, and wheat germ. It is a planar, unsaturated compound that has the ability to absorb light. Based on 12C/13C isotopic ratios of organic compounds found in the Murchison meteorite, it is believed that uracil, xanthine, and related molecules can also be formed extraterrestrially. Data from the Cassini mission, orbiting in the Saturn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Product (chemistry)
Products are the species formed from chemical reactions. During a chemical reaction, reactants are transformed into products after passing through a high energy transition state. This process results in the consumption of the reactants. It can be a spontaneous reaction or mediated by catalysts which lower the energy of the transition state, and by solvents which provide the chemical environment necessary for the reaction to take place. When represented in chemical equations, products are by convention drawn on the right-hand side, even in the case of reversible reactions. The properties of products such as their energies help determine several characteristics of a chemical reaction, such as whether the reaction is exergonic or endergonic. Additionally, the properties of a product can make it easier to extract and purify following a chemical reaction, especially if the product has a different state of matter than the reactants. Spontaneous reaction : R \rightarrow P *Where R is r ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
