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Glucose-1-phosphate
Glucose 1-phosphate (also called cori ester) is a glucose molecule with a phosphate group on the 1'-carbon. It can exist in either the α- or β-anomeric form. Reactions of α-glucose 1-phosphate Catabolic In glycogenolysis, it is the direct product of the reaction in which glycogen phosphorylase cleaves off a molecule of glucose from a greater glycogen structure. A deficiency of muscle glycogen phosphorylase is known as glycogen storage disease type V (McArdle Disease). To be utilized in cellular catabolism it must first be converted to glucose 6-phosphate by the enzyme phosphoglucomutase in a free equilibrium. One reason that cells form glucose 1-phosphate instead of glucose during glycogen breakdown is that the very polar phosphorylated glucose cannot leave the cell membrane and so is marked for intracellular catabolism. Phosphoglucomutase-1 deficiency is known as glycogen storage disease type 14 (GSD XIV). Anabolic In glycogenesis, free glucose 1-phosphate can also react wi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glycogenesis
Glycogenesis is the process of glycogen synthesis, in which glucose molecules are added to chains of glycogen for storage. This process is activated during rest periods following the Cori cycle, in the liver, and also activated by insulin in response to high glucose levels. Steps *Glucose is converted into glucose 6-phosphate by the action of glucokinase or hexokinase with conversion of ATP to ADP. * Glucose-6-phosphate is converted into glucose-1-phosphate by the action of phosphoglucomutase, passing through the obligatory intermediate glucose-1,6-bisphosphate. * Glucose-1-phosphate is converted into UDP-glucose by the action of the enzyme UDP-glucose pyrophosphorylase. Pyrophosphate is formed, which is later hydrolysed by pyrophosphatase into two phosphate molecules. * The enzyme glycogenin is needed to create initial short glycogen chains, which are then lengthened and branched by the other enzymes of glycogenesis. Glycogenin, a homodimer, has a tyrosine residue on each ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uridine Triphosphate
Uridine-5′-triphosphate (UTP) is a pyrimidine nucleoside triphosphate, consisting of the organic base uracil linked to the 1′ carbon of the ribose sugar, and esterified with tri-phosphoric acid at the 5′ position. Its main role is as substrate for the synthesis of RNA during transcription. UTP is the precursor for the production of CTP via the help of CTP Synthetase. UTP can be biosynthesized from UDP by Nucleoside Diphosphate Kinase after using phosphate group from ATP. UDP + ATP ⇌ UTP + ADP; both UTP and ATP are energetically equal. The homologue in DNA is thymidine triphosphate (TTP or dTTP). UTP also has a deoxyribose form (dUTP). Role in metabolism UTP also has the role of a source of energy or an activator of substrates in metabolic reactions, like that of ATP, but more specific. When UTP activates a substrate (like Glucose-1-phosphate), UDP-glucose is formed and inorganic phosphate is released. UDP-glucose enters the synthesis of glycogen. UTP is used in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glycogenolysis
Glycogenolysis is the breakdown of glycogen (n) to glucose-1-phosphate and glycogen (n-1). Glycogen branches are catabolized by the sequential removal of glucose monomers via phosphorolysis, by the enzyme glycogen phosphorylase. Mechanism The overall reaction for the breakdown of glycogen to glucose-1-phosphate is: : glycogen(n residues) + Pi glycogen(n-1 residues) + glucose-1-phosphate Here, glycogen phosphorylase cleaves the bond linking a terminal glucose residue to a glycogen branch by substitution of a phosphoryl group for the α →4linkage. Glucose-1-phosphate is converted to glucose-6-phosphate (which often ends up in glycolysis) by the enzyme phosphoglucomutase. Glucose residues are phosphorolysed from branches of glycogen until four residues before a glucose that is branched with a α →6linkage. Glycogen debranching enzyme then transfers three of the remaining four glucose units to the end of another glycogen branch. This exposes the α →6branching point, which ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glycogen
Glycogen is a multibranched polysaccharide of glucose that serves as a form of energy storage in animals, fungi, and bacteria. The polysaccharide structure represents the main storage form of glucose in the body. Glycogen functions as one of two forms of energy reserves, glycogen being for short-term and the other form being triglyceride stores in adipose tissue (i.e., body fat) for long-term storage. In humans, glycogen is made and stored primarily in the cells of the liver and skeletal muscle. In the liver, glycogen can make up 5–6% of the organ's fresh weight, and the liver of an adult, weighing 1.5 kg, can store roughly 100–120 grams of glycogen. In skeletal muscle, glycogen is found in a low concentration (1–2% of the muscle mass) and the skeletal muscle of an adult weighing 70 kg stores roughly 400 grams of glycogen. The amount of glycogen stored in the body—particularly within the muscles and liver—mostly depends on physical training, bas ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glycogen Synthase
Glycogen synthase (UDP-glucose-glycogen glucosyltransferase) is a key enzyme in glycogenesis, the conversion of glucose into glycogen. It is a glycosyltransferase () that catalyses the reaction of UDP-glucose and (1,4--D-glucosyl)n to yield UDP and (1,4--D-glucosyl)n+1. Structure Much research has been done on glycogen degradation through studying the structure and function of glycogen phosphorylase, the key regulatory enzyme of glycogen degradation. On the other hand, much less is known about the structure of glycogen synthase, the key regulatory enzyme of glycogen synthesis. The crystal structure of glycogen synthase from '' Agrobacterium tumefaciens'', however, has been determined at 2.3 A resolution. In its asymmetric form, glycogen synthase is found as a dimer, whose monomers are composed of two Rossmann-fold domains. This structural property, among others, is shared with related enzymes, such as glycogen phosphorylase and other glycosyltransferases of the GT-B superf ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organophosphates
In organic chemistry, organophosphates (also known as phosphate esters, or OPEs) are a class of organophosphorus compounds with the general structure , a central phosphate molecule with alkyl or aromatic substituents. They can be considered as esters of phosphoric acid. Like most functional groups, organophosphates occur in a diverse range of forms, with important examples including key biomolecules such as DNA, RNA and ATP, as well as many insecticides, herbicides, nerve agents and flame retardants. OPEs have been widely used in various products as flame retardants, plasticizers, and performance additives to engine oil. The popularity of OPEs as flame retardants came as a substitution for the highly regulated brominated flame retardants. The low cost of production and compatibility to diverse polymers made OPEs to be widely used in industry including textile, furniture, electronics as plasticizers and flame retardants. These compounds are added to the final product physi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gerty Cori
Gerty Theresa Cori (; August 15, 1896 – October 26, 1957) was an Austro-Hungarian and American biochemist who in 1947 was the third woman to win a Nobel Prize in science, and the first woman to be awarded the Nobel Prize in Physiology or Medicine, for her significant role in the "discovery of the course of the catalytic conversion of glycogen". Cori was born in Prague (then in the Austro-Hungarian Empire, now the Czech Republic). Gerty was not a nickname, but rather she was named after an Austrian warship. Growing up at a time when women were marginalized in science and allowed few educational opportunities, she gained admittance to medical school, where she met her future husband Carl Ferdinand Cori in an anatomy class; upon their graduation in 1920, they married. Because of deteriorating conditions in Europe, the couple emigrated to the United States in 1922. Gerty Cori continued her early interest in medical research, collaborating in the laboratory with Carl. She publish ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pentose Phosphate Pathway
The pentose phosphate pathway (also called the phosphogluconate pathway and the hexose monophosphate shunt and the HMP Shunt) is a metabolic pathway parallel to glycolysis. It generates NADPH and pentoses (5-carbon sugars) as well as ribose 5-phosphate, a precursor for the synthesis of nucleotides. While the pentose phosphate pathway does involve oxidation of glucose, its primary role is anabolic rather than catabolic. The pathway is especially important in red blood cells (erythrocytes). There are two distinct phases in the pathway. The first is the oxidative phase, in which NADPH is generated, and the second is the non-oxidative synthesis of 5-carbon sugars. For most organisms, the pentose phosphate pathway takes place in the cytosol; in plants, most steps take place in plastids. Like glycolysis, the pentose phosphate pathway appears to have a very ancient evolutionary origin. The reactions of this pathway are mostly enzyme-catalyzed in modern cells, however, they also occur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Beta-phosphoglucomutase
In enzymology, a β-phosphoglucomutase () is an enzyme that catalyzes the chemical reaction :β-D-glucose 1-phosphate \rightleftharpoons β-D-glucose 6-phosphate Hence, this enzyme has one substrate, β-D-glucose 1-phosphate, and one product, β-D-glucose 6-phosphate. This enzyme belongs to the family of isomerases, specifically the phosphotransferases (phosphomutases), which transfer phosphate groups within a molecule. The systematic name of this enzyme class is beta-D-glucose 1,6-phosphomutase. This enzyme participates in starch and sucrose metabolism. Structural studies 20 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 enzyme PDB. Some of the accession codes are , , , , , and . Most of these structures detail metal fluoride anal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alpha,alpha-trehalose Phosphorylase
In enzymology, an alpha,alpha-trehalose phosphorylase () is an enzyme that catalyzes the chemical reaction :alpha,alpha-trehalose + phosphate \rightleftharpoons D-glucose + beta-D-glucose 1-phosphate Thus, the two substrates of this enzyme are trehalose and phosphate, whereas its two products are D-glucose and beta-D-glucose 1-phosphate. This enzyme belongs to the family of glycosyltransferases, specifically the hexosyltransferases. The systematic name A systematic name is a name given in a systematic way to one unique group, organism, object or chemical substance, out of a specific population or collection. Systematic names are usually part of a nomenclature. A semisystematic name or semitrivial ... of this enzyme class is alpha,alpha-trehalose:phosphate beta-D-glucosyltransferase. This enzyme is also called trehalose phosphorylase. This enzyme participates in starch and sucrose metabolism. References * EC 2.4.1 Enzymes of unknown structure {{2.4-enzyme-st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kojibiose Phosphorylase
In enzymology, a kojibiose phosphorylase () is an enzyme that catalyzes the chemical reaction :2-alpha-D-glucosyl-D-glucose + phosphate \rightleftharpoons D-glucose + beta-D-glucose 1-phosphate Thus, the two substrates of this enzyme are kojibiose and phosphate, whereas its two products are D-glucose and beta-D-glucose 1-phosphate. This enzyme belongs to the family of glycosyltransferases, specifically the hexosyltransferases. The systematic name A systematic name is a name given in a systematic way to one unique group, organism, object or chemical substance, out of a specific population or collection. Systematic names are usually part of a nomenclature. A semisystematic name or semitrivial ... of this enzyme class is 2-alpha-D-glucosyl-D-glucose:phosphate beta-D-glucosyltransferase. References * * EC 2.4.1 Enzymes of unknown structure {{2.4-enzyme-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maltose Phosphorylase
In enzymology, a maltose phosphorylase () is an enzyme that catalyzes the chemical reaction :maltose + phosphate \rightleftharpoons D-glucose + beta-D-glucose 1-phosphate Thus, the two substrates of this enzyme are maltose and phosphate, whereas its two products are D-glucose and beta-D-glucose 1-phosphate. This enzyme belongs to the family of glycosyltransferases, specifically the hexosyltransferases. The systematic name A systematic name is a name given in a systematic way to one unique group, organism, object or chemical substance, out of a specific population or collection. Systematic names are usually part of a nomenclature. A semisystematic name or semitrivial ... of this enzyme class is maltose:phosphate 1-beta-D-glucosyltransferase. This enzyme participates in starch and sucrose metabolism. Structural studies As of late 2007, only one structure has been solved for this class of enzymes, with the PDB accession code . References * Boyer, P.D., Lardy, H. and Myr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
