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G6PC
Glucose-6-phosphatase, catalytic subunit (glucose 6-phosphatase alpha) is an enzyme that in humans is encoded by the ''G6PC'' gene. Glucose-6-phosphatase is an integral membrane protein of the endoplasmic reticulum that catalyzes the hydrolysis of D-glucose 6-phosphate to D-glucose and orthophosphate. It is a key enzyme in glucose homeostasis, functioning in gluconeogenesis and glycogenolysis. Defects in the enzyme cause glycogen storage disease type I (von Gierke disease). Interactive pathway map See also * G6PC2 * G6PC3 * glucose 6-phosphatase * glycogen storage disease type I References Further reading * * * * * * * * * * * * * * * * * * * {{refend ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glucose 6-phosphatase
The enzyme glucose 6-phosphatase (EC 3.1.3.9, G6Pase; systematic name D-glucose-6-phosphate phosphohydrolase) catalyzes the hydrolysis of glucose 6-phosphate, resulting in the creation of a phosphate group and free glucose: : D-glucose 6-phosphate + H2O = D-glucose + phosphate Glucose is then exported from the cell via glucose transporter membrane proteins. This catalysis completes the final step in gluconeogenesis and therefore plays a key role in the homeostatic regulation of blood glucose levels. Glucose 6-phosphatase is a complex of multiple component proteins, including transporters for G6P, glucose, and phosphate. The main phosphatase function is performed by the glucose 6-phosphatase catalytic subunit. In humans, there are three isozymes of the catalytic subunit: glucose 6-phosphatase-α, encoded by G6PC; IGRP, encoded by G6PC2; and glucose 6-phosphatase-β, encoded by G6PC3. Glucose 6-phosphatase-α and glucose 6-phosphatase-β are both functional phosphohydrola ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
G6PC3
Glucose-6-phosphatase 3, also known as glucose-6-phosphatase beta, is an enzyme that in humans is encoded by the ''G6PC3'' gene. Function This gene encodes the catalytic subunit of glucose 6-phosphatase (G6Pase). G6Pase is located in the endoplasmic reticulum (ER) and catalyzes the hydrolysis of glucose 6-phosphate to glucose and phosphate in the last step of the gluconeogenic and glycogenolytic pathways. Clinical significance Mutations in this gene result in autosomal recessive severe congenital neutropenia Severe congenital neutropenia (SCN), also often known as Kostmann syndrome or disease, is a group of rare disorders that affect myelopoiesis, causing a congenital form of neutropenia, usually without other physical malformations. SCN manifests in .... G6PC3 deficiency results in a phenotypic continuum. At one end the affected individuals have only neutropenia and related complications but no other organ is affected. This is sometimes referred to as ''non-syndromic'' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
G6PC2
Glucose-6-phosphatase 2 is an enzyme that in humans is encoded by the ''G6PC2'' gene. Function This gene encodes an enzyme belonging to the glucose-6-phosphatase catalytic subunit family. These enzymes are part of a multicomponent integral membrane system that catalyzes the hydrolysis of glucose-6-phosphate, the terminal step in gluconeogenic and glycogenolytic H04A Glycogenolytic hormones H04AA Glycogenolytic hormones :H04AA01 Glucagon References H04 {{Short pages monitor [Baidu] |
Glycogen Storage Disease Type I
Glycogen storage disease type I (GSD I) is an inherited disease that results in the liver being unable to properly break down stored glycogen. This impairment disrupts the liver's ability to break down stored glycogen that is necessary to maintain adequate blood sugar levels. GSD I is divided into two main types, GSD Ia and GSD Ib, which differ in cause, presentation, and treatment. GSD Ia is caused by a deficiency in the enzyme glucose-6-phosphatase, while GSD Ib is caused a deficiency in the enzyme glucose-6-phosphate translocase. Since glycogenolysis is the principal metabolic mechanism by which the liver supplies glucose to the body during periods of fasting, both deficiencies cause severe low blood sugar and, over time, excess glycogen storage in the liver and (in some cases) the kidneys. GSD I patients typically present with an enlarged liver from non-alcoholic fatty liver disease as the result of this glycogen buildup. Other functions of the liver and kidneys are initiall ... [...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] |
Gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a basic unit of heredity and the molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protein-coding genes and noncoding genes. During gene expression, the DNA is first copied into RNA. The RNA can be directly functional or be the intermediate template for a protein that performs a function. The transmission of genes to an organism's offspring is the basis of the inheritance of phenotypic traits. These genes make up different DNA sequences called genotypes. Genotypes along with environmental and developmental factors determine what the phenotypes will be. Most biological traits are under the influence of polygenes (many different genes) as well as gen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Membrane Protein
Membrane proteins are common proteins that are part of, or interact with, biological membranes. Membrane proteins fall into several broad categories depending on their location. Integral membrane proteins are a permanent part of a cell membrane and can either penetrate the membrane (transmembrane) or associate with one or the other side of a membrane ( integral monotopic). Peripheral membrane proteins are transiently associated with the cell membrane. Membrane proteins are common, and medically important—about a third of all human proteins are membrane proteins, and these are targets for more than half of all drugs. Nonetheless, compared to other classes of proteins, determining membrane protein structures remains a challenge in large part due to the difficulty in establishing experimental conditions that can preserve the correct conformation of the protein in isolation from its native environment. Function Membrane proteins perform a variety of functions vital to the sur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gluconeogenesis
Gluconeogenesis (GNG) is a metabolic pathway that results in the generation of glucose from certain non-carbohydrate carbon substrates. It is a ubiquitous process, present in plants, animals, fungi, bacteria, and other microorganisms. In vertebrates, gluconeogenesis occurs mainly in the liver and, to a lesser extent, in the cortex of the kidneys. It is one of two primary mechanisms – the other being degradation of glycogen ( glycogenolysis) – used by humans and many other animals to maintain blood sugar levels, avoiding low levels (hypoglycemia). In ruminants, because dietary carbohydrates tend to be metabolized by rumen organisms, gluconeogenesis occurs regardless of fasting, low-carbohydrate diets, exercise, etc. In many other animals, the process occurs during periods of fasting, starvation, low-carbohydrate diets, or intense exercise. In humans, substrates for gluconeogenesis may come from any non-carbohydrate sources that can be converted to pyruvate or intermediates ... [...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] |
