| Glucose-6-phosphate | |
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| IUPAC name | (3,4,5,6- tetrahydroxytetrahydropyran- 2-yl) methoxyphosphonic acid |
| Identifiers | |
| CAS number | [56-73-5] |
| PubChem | |
| MeSH | |
| SMILES | C(C1C(C(C(C(O1)O)O)O)O)OP(=O)(O)O |
| Properties | |
| Molecular formula | C6H13O9P |
| Molar mass | 260. IUPAC Nomenclature is a system of naming Chemical compounds and of describing the science of Chemistry in general CAS registry numbers are unique numerical identifiers for Chemical compounds Polymers biological sequences mixtures and Alloys They are also referred to PubChem is a Database of chemical Molecules The system is maintained by the National Center for Biotechnology Information (NCBI a component Medical Subject Headings ( MeSH) is a huge Controlled vocabulary (or metadata system for the purpose of indexing journal articles and books A chemical formula is a way of expressing information about the Atoms that constitute a particular Chemical compound, and how the relationship between those atoms changes Molar mass, symbol M, is the Mass of one mole of a substance ( Chemical element or Chemical compound) 136 |
| Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references |
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Glucose 6-phosphate (also known as Robison ester) is glucose sugar phosphorylated on carbon 6. In Chemistry, the standard state of a material is its state at 1 bar (100 Kilopascals exactly Glucose (Glc a Monosaccharide (or simple Sugar) also known as grape sugar, is an important Carbohydrate in Biology. Phosphorylation is the addition of a Phosphate (PO4 group to a Protein molecule or a small molecule This compound is very common in cells as the vast majority of glucose entering a cell will become phosphorylated in this way. The cell is the structural and functional unit of all known living Organisms It is the smallest unit of an organism that is classified as living and is often called
Because of its prominent position in cellular chemistry, glucose 6-phosphate has many possible fates within the cell. It lies at the start of two major metabolic pathways:
In addition to these metabolic pathways, glucose 6-phosphate may also be converted to glycogen or starch for storage. In Biochemistry, a metabolic pathway is a series of chemical reactions occurring within a cell. See also Gluconeogenesis, which carries out a process wherein glucose is synthesized rather than catabolized The pentose phosphate pathway (also called Phosphogluconate Pathway or HexoseMonophosphate Shunt shunt is a process that serves to generate NADPH and the synthesis of pentose Glycogen is a Polysaccharide of Glucose (Glc which functions as the secondary short term energy storage in Animal cells Starch, CAS # 9005-25-8 Chemical formula (C6H10O5n is a Polysaccharide This storage is in the liver and muscles in the form of glycogen for most multicellular animals, and in intracellular starch or glycogen granules for most other organisms. The liver is a vital organ in the human body and is present in Vertebrates and some other animals Muscle (from Latin musculus, diminutive of mus "mouse" is contractile tissue of the body and is derived from the Not to be confused with Intercellular, meaning "between cells"
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Production of glucose 6-phosphate
From glucose
Within a cell, glucose 6-phosphate is produced by phosphorylation of glucose on the sixth carbon. Glucose (Glc a Monosaccharide (or simple Sugar) also known as grape sugar, is an important Carbohydrate in Biology. This is catalyzed by the enzyme hexokinase in most cells, and, in higher animals, glucokinase in certain cells, most notably liver cells. Enzymes are Biomolecules that catalyze ( ie increase the rates of Chemical reactions Almost all enzymes are Proteins Variation across species Hexokinases have been found in every organism checked ranging from bacteria, Yeast, and Plants to humans and other Vertebrates Glucokinase ( is an Enzyme that facilitates Phosphorylation of Glucose to Glucose-6-phosphate. One molecule of ATP is consumed in this reaction. Adenosine-5'-triphosphate ( ATP) is a multifunctional Nucleotide that is most important as a " molecular currency" of intracellular Energy
| D-Glucose | Hexokinase | α-D-Glucose 6-phosphate | |
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| ATP | ADP | ||
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Compound C00031 at KEGG Pathway Database. Glucose (Glc a Monosaccharide (or simple Sugar) also known as grape sugar, is an important Carbohydrate in Biology. Variation across species Hexokinases have been found in every organism checked ranging from bacteria, Yeast, and Plants to humans and other Vertebrates Glucose 6-phosphate (also known as Robison ester) is Glucose sugar Phosphorylated on carbon 6 Adenosine-5'-triphosphate ( ATP) is a multifunctional Nucleotide that is most important as a " molecular currency" of intracellular Energy Adenosine diphosphate, abbreviated ADP, is a Nucleotide. It is an Ester of Pyrophosphoric acid with the Nucleoside Adenosine KEGG ( Kyoto Encyclopedia of Genes and Genomes) is a collection of Online databases dealing with Genomes Enzymatic pathways and biological chemicals Enzyme 2.7.1.1 at KEGG Pathway Database. KEGG ( Kyoto Encyclopedia of Genes and Genomes) is a collection of Online databases dealing with Genomes Enzymatic pathways and biological chemicals Compound C00668 at KEGG Pathway Database. KEGG ( Kyoto Encyclopedia of Genes and Genomes) is a collection of Online databases dealing with Genomes Enzymatic pathways and biological chemicals Reaction R01786 at KEGG Pathway Database. KEGG ( Kyoto Encyclopedia of Genes and Genomes) is a collection of Online databases dealing with Genomes Enzymatic pathways and biological chemicals
The major reason for the immediate phosphorylation of glucose is to prevent diffusion out of the cell. The phosphorylation adds a charged phosphate group so the glucose 6-phosphate cannot easily cross the cell membrane. A phosphate, an Inorganic chemical, is a salt of Phosphoric acid. Glucose 6-phosphate (also known as Robison ester) is Glucose sugar Phosphorylated on carbon 6 The cell membrane (also called the plasma membrane, plasmalemma, or "phospholipid bilayer" is a Selectively permeable Lipid bilayer
From glycogen
Glucose-6-phosphate is also produced during glycogenolysis from glucose-1-phosphate, the first product of the breakdown of glycogen polymers. Glycogenolysis (also known as "Glycogenlysis" is the Catabolism of Glycogen by removal of a Glucose monomer through cleavage with inorganic Glycogen is a Polysaccharide of Glucose (Glc which functions as the secondary short term energy storage in Animal cells
Fate 1: Pentose Phosphate Pathway
When the ratio of NADP+ : NADPH increases, the body realizes it needs to produce more NADPH (a reducing agent for several reactions like fatty acid synthesis and glutathione reduction in erythrocytes). Red blood cells are the most common type of Blood cell and the Vertebrate body's principal means of delivering Oxygen to the body tissues via the Blood This will cause the G6P to be dehydrogenated by glucose 6-phosphate dehydrogenase. This reversible reaction is the initial step of the pentose phosphate pathway, which generates the useful cofactor NADPH as well as ribulose 5-phosphate, a carbon source for the synthesis of other molecules. The pentose phosphate pathway (also called Phosphogluconate Pathway or HexoseMonophosphate Shunt shunt is a process that serves to generate NADPH and the synthesis of pentose Also, if the body needs nucleotide precursors of DNA for growth and synthesis, G6P will also be dehydrogenated and enter the pentose phosphate pathway.
Fate 2: Glycolysis
If the cell needs energy or carbon skeletons for synthesis then glucose 6-phosphate is targeted for glycolysis. See also Gluconeogenesis, which carries out a process wherein glucose is synthesized rather than catabolized Glucose 6-phosphate is first isomerized to fructose-6-phosphate by phosphoglucose isomerase. Fructose 6-phosphate (also known as the Neuberg ester) is Fructose sugar Phosphorylated on carbon 6 (ie Glucose-6-phosphate isomerase, or phosphoglucose isomerase, is an Enzyme ( that catalyzes the conversion of Glucose-6-phosphate into Fructose-6-phosphate
| α-D-Glucose 6-phosphate | Phosphoglucose isomerase | β-D-Fructose 6-phosphate | |
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| Phosphoglucose isomerase | |||
Compound C00668 at KEGG Pathway Database. Glucose 6-phosphate (also known as Robison ester) is Glucose sugar Phosphorylated on carbon 6 Glucose-6-phosphate isomerase, or phosphoglucose isomerase, is an Enzyme ( that catalyzes the conversion of Glucose-6-phosphate into Fructose-6-phosphate Fructose 6-phosphate (also known as the Neuberg ester) is Fructose sugar Phosphorylated on carbon 6 (ie Glucose-6-phosphate isomerase, or phosphoglucose isomerase, is an Enzyme ( that catalyzes the conversion of Glucose-6-phosphate into Fructose-6-phosphate KEGG ( Kyoto Encyclopedia of Genes and Genomes) is a collection of Online databases dealing with Genomes Enzymatic pathways and biological chemicals Enzyme 5.3.1.9 at KEGG Pathway Database. KEGG ( Kyoto Encyclopedia of Genes and Genomes) is a collection of Online databases dealing with Genomes Enzymatic pathways and biological chemicals Compound C05345 at KEGG Pathway Database. KEGG ( Kyoto Encyclopedia of Genes and Genomes) is a collection of Online databases dealing with Genomes Enzymatic pathways and biological chemicals Reaction R00771 at KEGG Pathway Database. KEGG ( Kyoto Encyclopedia of Genes and Genomes) is a collection of Online databases dealing with Genomes Enzymatic pathways and biological chemicals
This reaction converts glucose 6-phosphate to fructose 6-phosphate in preparation for phosphorylation to Fructose-1,6-bisphosphate. Fructose 6-phosphate (also known as the Neuberg ester) is Fructose sugar Phosphorylated on carbon 6 (ie Fructose 16-phosphate is Fructose sugar Phosphorylated on carbons 1 and 6 (ie The addition of the 2nd phosphoryl group to produce Fructose-1,6-bisphosphate is an irreversible step, and so is used to irreversibly target the glucose 6-phosphate breakdown to provide energy for ATP production via glycolysis. See also Gluconeogenesis, which carries out a process wherein glucose is synthesized rather than catabolized
Fate 3: Storage as Glycogen
If blood glucose levels are high, the body needs a way to store the excess glucose. After being converted to G6P, phosphoglucose mutase (isomerase) can turn the molecule into glucose-1-phosphate. Glucose-6-phosphate isomerase, or phosphoglucose isomerase, is an Enzyme ( that catalyzes the conversion of Glucose-6-phosphate into Fructose-6-phosphate Glucose-1-phosphate can then be combined with uridine triphosphate (UTP) to form UDP-glucose. This reaction is driven by the hydrolysis of pyrophosphate that is released in the reaction. Now, the activated UDP-glucose can add to a growing glycogen molecule with the help of glycogen synthase. Glycogen synthase ( UDP-glucose-glycogen glucosyltransferase') is a Glycosyltransferase Enzyme ( EC number 2 This is a very efficient storage mechanism for glucose since it costs the body only 1 ATP to store the 1 glucose molecule and virtually no energy to remove it from storage. It is important to note that glucose-6-phosphate is an allosteric activator of glycogen synthase, which makes sense because when the level of glucose is high the body should store the excess glucose as glycogen. On the other hand, glycogen synthase is inhibited when it is phosphorylated by protein kinase during times of high stress or low blood glucose levels (via hormone induction by glucagon or adrenaline). Glucagon is an important Hormone involved in Carbohydrate metabolism.
When the body needs glucose for energy, glycogen phosphorylase, with the help of an orthophosphate, can cleave away a molecule from the glycogen chain. Glycogen phosphorylase is one of the Phosphorylase Enzymes ( It breaks up Glycogen into Glucose Subunits. The cleaved molecule is in the form of glucose-1-phosphate which can be converted into G6P by phosphoglucomutase. Next, the phosphoryl group on G6P can be cleaved by glucose-6-phosphatase so that a free glucose can be formed. This free glucose can pass through membranes and can enter the bloodstream to travel to other places in the body.
Fate 4: Dephosphorylation and Release into Bloodstream
Liver cells possess glucose-6-phosphatase, which removes the phosphate group from glucose-6-phosphate produced during glycogenolysis or gluconeogenesis. Glucose 6-phosphatase (Glc-6-Pase is an Enzyme that hydrolyzes Glucose-6-phosphate resulting in the creation of a phosphate group and free glucose Glycogenolysis (also known as "Glycogenlysis" is the Catabolism of Glycogen by removal of a Glucose monomer through cleavage with inorganic Gluconeogenesis (abreviated GNG) is a Metabolic pathway that results in the generation of Glucose from non- Carbohydrate carbon substrates such The free glucose is sent into the bloodstream for uptake by other cells.
References
- Berg, Jeremy M. ; Tymoczko, Stryer (2002). Biochemistry, 5th, New York: W. H. Freeman and Company. ISBN 0-7167-3051-0.
See also
- Glucose
- Glycogen
- Glucose 1-phosphate
- Pentose phosphate pathway
- Glucose-6-phosphate dehydrogenase deficiency
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