NationMaster - Encyclopedia: Coenzyme

Coenzymes are small organic non-protein molecules that carry chemical groups between enzymes. Many coenzymes are phosphorylated water-soluble vitamins. However, nonvitamins may also be coenzymes, such as ATP, the biochemical carrier of phosphate groups, or coenzyme A the coenzyme that carries acyl groups. Coenzyme Q is unusual as it carries electrons between enzymes by diffusing within cell membranes, as this coenzyme is not water soluble. The term coenzymes is commonly used loosely, and coenzymes can also be defined as organic, non-protein cofactors.^[1] Coenzymes are also sometimes referred to as cosubstrates, but this usage is unusual. Image File history File links Download high-resolution version (1532x1366, 26 KB) I, the creator of this work, hereby release it into the public domain. ... Image File history File links Download high-resolution version (1532x1366, 26 KB) I, the creator of this work, hereby release it into the public domain. ... Benzene is the simplest of the arenes, a family of organic compounds An organic compound is any member of a large class of chemical compounds whose molecules contain carbon and hydrogen; therefore, carbides, carbonates, carbon oxides and elementary carbon are not organic (see below for more on the definition controversy... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... In chemistry, a molecule is an aggregate of two or more atoms in a definite arrangement held together by chemical bonds [1] [2] [3] [4] [5]. Chemical substances are not infinitely divisible into smaller fractions of the same substance: a molecule is generally considered the smallest particle of a pure... Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ... A phosphorylated serine residue Phosphorylation is the addition of a phosphate (PO4) group to a protein or a small molecule or the introduction of a phosphate group into an organic molecule. ... Impact of a drop of water. ... Retinol (Vitamin A) For the record label, see Vitamin Records Vitamins are nutrients required in very small amounts for essential metabolic reactions in the body. ... Adenosine 5-triphosphate (ATP) is a multifunctional nucleotide that is most important as a molecular currency of intracellular energy transfer. ... Above is a ball-and-stick model of the inorganic hydrogenphosphate anion (HPO42âˆ’). Colour coding: P (orange); O (red); H (white). ... Acetyl Coenzyme A Acetyl-CoA Coenzyme A (CoA, CoASH, or HSCoA) is a coenzyme, notable for its role in the synthesis and oxidization of fatty acids, and the oxidation of pyruvate in the citric acid cycle. ... In chemistry, the terms acyl or acyl group refer to a functional group obtained from an acid by removal of a hydroxyl group. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... A cofactor is any substance that needs to be present in addition to an enzyme to catalyze a certain reaction. ...

Coenzymes are consumed in the reactions in which they are substrates, for example: the coenzyme NADH is converted to NAD⁺ by oxidoreductases. Coenzymes are however regenerated and their concentration maintained at a steady level in the cell.

A special subset of coenzymes are prosthetic groups. These have more in common with cofactors since they are tightly bound to enzymes and are not released as part of the reaction. Prosthetic groups include molybdopterin, lipoamide and biotin. A coenzyme is an organic non-protein molecule that is a functional part of an enzyme. ... A cofactor is any substance that needs to be present in addition to an enzyme to catalyze a certain reaction. ... Molybdopterins are a class of biochemical cofactors that are used in many different enzymes. ... Lipoamide is a trivial name for 6,8-dithiooctanoic amide. ... Vitamin H redirects here. ...

See also

Acetyl Coenzyme A Acetyl-CoA Coenzyme A (CoA, CoASH, or HSCoA) is a coenzyme, notable for its role in the synthesis and oxidization of fatty acids, and the oxidation of pyruvate in the citric acid cycle. ... Adenosine 5-triphosphate (ATP) is a multifunctional nucleotide that is most important as a molecular currency of intracellular energy transfer. ... This coenzyme transfers glycosyl-groups from glucose. ... Cyanocobalamin is a vitamin commonly known as vitamin B12 (or B12 for short). ... Coenzyme Q (CoQ), also known as ubiquinone or ubiquinol, is a biologically active quinone with an isoprenoid side chain, related in structure to vitamin K and vitamin E. // History Coenzyme Q was first discovered in 1957 by professor F. L. Crane and colleagues at the University of Wisconsin Enzyme Institute. ... Nicotinamide adenine dinucleotide (NAD+) Nicotinamide adenine dinucleotide (NAD+) and nicotinamide adenine dinucleotide phosphate (NADP) are two important cofactors found in cells. ... Molybdopterins are a class of biochemical cofactors that are used in many different enzymes. ... This article deals with the molecular aspects of ascorbic acid. ... Vitamin C is a nutrient required in very small amounts to allow a range of essential metabolic reactions in the body. ... A cofactor is any substance that needs to be present in addition to an enzyme to catalyze a certain reaction. ... Neuraminidase ribbon diagram An enzyme (in Greek en = in and zyme = blend) is a protein, or protein complex, that catalyzes a chemical reaction and also controls the 3D orientation of the catalyzed substrates. ...

References

External links

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Proteins: enzymes

Active site - Binding site - Catalytically perfect enzyme - Coenzyme - Cofactor - EC number - Enzyme catalysis - Enzyme kinetics - Enzyme inhibitor - Lineweaver-Burk plot - Michaelis-Menten kinetics A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ... The active site of an enzyme is the binding site where catalysis occurs. ... A binding site is a region on a protein to which specific ligands bind. ... Catalytically perfect enzyme or kineticall perfect enzyme is an enzyme that catalyzes so efficiently, that almost every time enzyme meets its substrate, the reaction occurs. ... A cofactor is any substance that needs to be present in addition to an enzyme to catalyze a certain reaction. ... The Enzyme Commission number (EC number) is a numerical classification scheme for enzymes, based on the chemical reactions they catalyze. ... Enzyme catalysis is the catalysis of chemical reactions by enzyme molecules. ... It has been suggested that this article or section be merged with Enzyme. ... HIV protease in a complex with the protease inhibitor ritonavir. ... In biochemistry, the Lineweaver-Burk plot (or double reciprocal plot) is a graphical representation of the Lineweaver-Burk equation of enzyme kinetics, described by Hans Lineweaver and Dean Burk in 1934. ... Michaelis-Menten kinetics describes the kinetics of many enzymes. ...

EC1 Oxidoreductases/list (alcohol oxidoreductases, dehydrogenase, hydroxylase, oxygenase, oxidase, peroxidase) - EC2 Transferases/list (methyltransferase, acyltransferase, glycosyltransferase, transaminase, phosphotransferase, polymerase, kinase) - EC3 Hydrolases/list (esterase, DNA glycosylases, glycosidase, protease, helicase) - EC4 Lyases/list (carboxy-lyases, aldolase, dehydratase, synthase) - EC5 Isomerases/list (mutase, topoisomerase) - EC6 Ligases/list (DNA ligase, aminoacyl tRNA synthetase) In biochemistry, an oxidoreductase is an enzyme that catalyzes the transfer of electrons from one molecule (the oxidant, also called the hydrogen donor or electron donor) to another (the reductant, also called the hydrogen acceptor or electron acceptor). ... This list contains a list of EC numbers for the first group, EC 1, oxidoreducatases, placed in numerical order as determined by the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology. ... Functional group of an alcohol molecule. ... A dehydrogenase is an enzyme that oxidizes a substrate by transferring one or more protons and a pair of electrons to an acceptor, usually NAD/NADP or a flavin coenzyme such as FAD or FMN. Common examples of dehydrogenase enzymes in the TCA cycle are pyruvate dehydrogenase, isocitrate dehydrogenase, and... Hydroxylation is any chemical process that introduces one or more hydroxyl groups (-OH) into a compound (or radical) thereby oxidising it. ... An oxygenase is any enzyme that oxidizes a substrate by transferring the oxygen from molecular oxygen O2 (as in air) to it. ... An oxidase is any enzyme that catalyzes an oxidation/reduction reaction involving molecular oxygen (O2) as the electron acceptor. ... Glutathione Peroxidase 1 A peroxidase (eg. ... In biochemistry, a transferase is an enzyme that catalyzes the transfer of a functional group (e. ... This list contains a list of EC numbers for the second group, EC 2, transferases, placed in numerical order as determined by the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology. ... Methyltransferase can refer to: DNA methyltransferase Histone methyltransferase Category: ... Acetyl Acyltransferase is a type of transferase enzyme which acts upon acyl groups. ... Glycosyltransferases are a group of enzymes that act as a catalyst for the transfer of a monosaccharide from a glycosylamine derivative to an acceptor. ... In biochemistry, a transaminase or an aminotransferase is an enzyme that catalyzes a type of reaction between an amino acid and an Î±-keto acid. ... Phosphotransferase is a category of enzymes with the quality of catalyzing phosphorylation. ... ITaq DNA polymerase A polymerase (EC 2. ... In biochemistry, a kinase is a type of enzyme that transfers phosphate groups from high-energy donor molecules, such as ATP, to specific target molecules (substrates); the process is termed phosphorylation. ... In biochemistry, a hydrolase is an enzyme that can break a chemical bond by hydrolysis. ... This list contains a list of EC numbers for the third group, EC 3, hydrolases, placed in numerical order as determined by the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology. ... An esterase is an hydrolase enzyme that splits esters into a acid and an alcohol in a chemical reaction with water called hydrolysis. ... DNA glycosylases are a family of enzymes involved in base excision repair. ... Glycoside hydrolases (also called glycosidases) catalyze the hydrolysis of the glycosidic linkage to generate two smaller sugars. ... Proteases (proteinases, peptidases, or proteolytic enzymes) are enzymes that break peptide bonds between amino acids of proteins. ... Helicases are a class of enzymes vital to all living organisms. ... In biochemistry, a lyase is an enzyme that breaks various chemical bonds by means other than hydrolysis and oxidation, often forming a new double bond or a new ring structure. ... This list contains a list of EC numbers for the fourth group, EC 4, lyases, placed in numerical order as determined by the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology. ... Carboxy-lyases, also known as decarboxylases, are carbon-carbon lyases that add or remove a carboxyl group from organic compounds. ... Aldolase is an enzyme which catalyses the aldol reaction: The substrate, fructose 1,6-bisphosphate (F-1,6-BP) is broken down into glyceraldehyde 3-phosphate and dihydroxyacetone phosphate (DHAP). ... Dehydratase is an enzyme that catalyzes the removal of oxygen and hydrogen from organic compounds in the form of water. ... In biochemistry, a synthase is an enzyme which catalyzes a synthesis process. ... In biochemistry, an isomerase is any enzyme that catalyses the interconversion of isomers. ... This list contains a list of EC numbers for the fifth group, EC 5, isomerases, placed in numerical order as determined by the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology. ... An enzyme that catalyzes the shifting of a functional group from one position to another within the same molecule. ... Topoisomerases (type I: EC 5. ... In biochemistry, a ligase (from the Latin verb ligÄre â€” to bind or to glue together) is an enzyme that can catalyse the joining of two large molecules by forming a new chemical bond, usually with accompanying hydrolysis of a small chemical group pendant to one of the larger molecules. ... This list contains a list of EC numbers for the sixth group, EC 6, ligases, placed in numerical order as determined by the Nomenclature Committee of the International Union of Biochemistry and Molecular Biology. ... It has been suggested that sticky end/blunt end be merged into this article or section. ... An aminoacyl tRNA synthetase (abbreviated aaRs) is an enzyme that catalyzes the binding of a specific amino acid to a tRNA to form an aminoacyl-tRNA. The synthetase hydrolyzes ATP to bind the appropriate amino acid to the 3 hydroxyl of the tRNA molecule. ...