''sn''-Glycerol 3-phosphate is the organic ion with the formula HOCH₂CH(OH)CH₂OPO₃^2-. It is one of three

stereoisomer In stereochemistry, stereoisomerism, or spatial isomerism, is a form of isomerism in which molecules have the same molecular formula and sequence of bonded atoms (constitution), but differ in the three-dimensional orientations of their atoms in ...

s of the ester of dibasic phosphoric acid (HOPO₃^2-) and

glycerol Glycerol (), also called glycerine in British English and glycerin in American English, is a simple triol compound. It is a colorless, odorless, viscous liquid that is sweet-tasting and non-toxic. The glycerol backbone is found in lipids known ...

. It is a component of

glycerophospholipid Glycerophospholipids or phosphoglycerides are glycerol-based phospholipids. They are the main component of biological membranes. Two major classes are known: those for bacteria and eukaryotes and a separate family for archaea. Structures The t ...

s. Equally appropriate names in biochemical context include glycerol-3-phosphate, 3-''O''-phosphonoglycerol, 3-phosphoglycerol; and Gro3P. From a historical reason, it is also known as -glycerol 3-phosphate, -glycerol 1-phosphate, -α-glycerophosphoric acid.

Biosynthesis

Glycerol 3-phosphate is synthesized by reducing dihydroxyacetone phosphate (DHAP), an intermediate in

glycolysis Glycolysis is the metabolic pathway that converts glucose () into pyruvate (). The free energy released in this process is used to form the high-energy molecules adenosine triphosphate (ATP) and reduced nicotinamide adenine dinucleotide (NADH ...

. The reduction is catalyzed by glycerol-3-phosphate dehydrogenase. DHAP and thus glycerol 3-phosphate can also be synthesized from

amino acids Amino acids are organic compounds that contain both amino and carboxylic acid functional groups. Although hundreds of amino acids exist in nature, by far the most important are the alpha-amino acids, which comprise proteins. Only 22 alpha am ...

and

citric acid cycle The citric acid cycle (CAC)—also known as the Krebs cycle or the TCA cycle (tricarboxylic acid cycle)—is a series of chemical reactions to release stored energy through the oxidation of acetyl-CoA derived from carbohydrates, fats, and prot ...

intermediates via the glyceroneogenesis pathway. : Dihydroxyacetonphosphat Skelett

+ NAD(P)H + H⁺ → Glycerin-3-phosphat Skelett

+ NAD(P)⁺ It is also synthesized by the

phosphorylation In chemistry, phosphorylation is the attachment of a phosphate group to a molecule or an ion. This process and its inverse, dephosphorylation, are common in biology and could be driven by natural selection. Text was copied from this source, wh ...

, which is generated by hydrolysis of fats. This esterification is catalyzed by

glycerol kinase Glycerol kinase, encoded by the gene ''GK'', is a phosphotransferase enzyme involved in triglycerides and glycerophospholipids synthesis. Glycerol kinase catalyzes the transfer of a phosphate from ATP to glycerol thus forming glycerol 3-phosph ...

. :

+ ATP →

ADP Adp or ADP may refer to: Aviation * Aéroports de Paris, airport authority for the Parisian region in France * Aeropuertos del Perú, airport operator for airports in northern Peru * SLAF Anuradhapura, an airport in Sri Lanka * Ampara Airp ...

Metabolism and biological function

Glycerol 3-phosphate is a starting material for ''de novo'' synthesis of

glycerolipid Lipids are a broad group of naturally-occurring molecules which includes fats, waxes, sterols, fat-soluble vitamins (such as vitamins A, D, E and K), monoglycerides, diglycerides, phospholipids, and others. The functions of lipids include s ...

s. In

eukaryotes Eukaryotes () are organisms whose cells have a nucleus. All animals, plants, fungi, and many unicellular organisms, are Eukaryotes. They belong to the group of organisms Eukaryota or Eukarya, which is one of the three domains of life. Bacter ...

, it is first acylated on its ''sn''-1 position by an ER- or mitochondrial membrane enzyme,

glycerol-3-phosphate O-acyltransferase In enzymology, a glycerol-3-phosphate O-acyltransferase () is an enzyme that catalyzes the chemical reaction :acyl-CoA + sn-glycerol 3-phosphate \rightleftharpoons CoA + 1-acyl-sn-glycerol 3-phosphate Thus, the two substrates of this enzyme are ...

. A second acyl group is subsequently installed on the ''sn''-2 position making

phosphatidic acid Phosphatidic acids are anionic phospholipids important to cell signaling and direct activation of lipid-gated ion channels. Hydrolysis of phosphatidic acid gives rise to one molecule each of glycerol and phosphoric acid and two molecules of fatty ac ...

s. :

Acyl-CoA Acyl-CoA is a group of coenzymes that metabolize fatty acids. Acyl-CoA's are susceptible to beta oxidation, forming, ultimately, acetyl-CoA. The acetyl-CoA enters the citric acid cycle, eventually forming several equivalents of ATP. In this wa ...

→

Lysophosphatidic acid Lysophosphatidic acid (LPA) is a phospholipid derivative that can act as a signaling molecule. Function LPA acts as a potent mitogen due to its activation of three high-affinity G-protein-coupled receptors called LPAR1, LPAR2, and LPAR3 (als ...

CoA Coa may refer to: Places * Coa, County Fermanagh, a rural community in County Fermanagh, Northern Ireland * Côa River, a tributary of the Douro, Portugal ** Battle of Coa, part of the Peninsular War period of the Napoleonic Wars ** Côa Valley ...

Glycerol-1-phosphatase catalyzes the hydrolysis of glycerol 3-phosphate to regenerate

, allowing glycerol fermentation to produce glycerol from

glucose Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, u ...

through glycolysis pathway. A number of organisms express this enzyme. : Glycerin-3-phosphat Skelett

+ H₂O →

+ Pi

Shuttle system

Glycerol-3-phosphate dehydrogenases are located both in the

cytosol The cytosol, also known as cytoplasmic matrix or groundplasm, is one of the liquids found inside cells ( intracellular fluid (ICF)). It is separated into compartments by membranes. For example, the mitochondrial matrix separates the mitochondri ...

and the intermembrane face of mitochondrial inner membrane. Glycerol 3-phosphate (G3P) and dihydroxyacetone phosphate (DHAP) are molecules so small that they can permeate the mitochondrial outer membrane through porins and shuttle between two dehydrogenases. Using this shuttle system,

NADH Nicotinamide adenine dinucleotide (NAD) is a coenzyme central to metabolism. Found in all living cells, NAD is called a dinucleotide because it consists of two nucleotides joined through their phosphate groups. One nucleotide contains an aden ...

generated by cytosolic metabolisms including glycolysis is reoxidized to NAD⁺ reducing DHAP to G3P, and the reducing equivalent can be used for generating a

proton gradient An electrochemical gradient is a gradient of electrochemical potential, usually for an ion that can move across a membrane. The gradient consists of two parts, the chemical gradient, or difference in solute concentration across a membrane, and ...

across the mitochondrial inner membrane by coupling and oxidizing G3P and reducing

quinone The quinones are a class of organic compounds that are formally "derived from aromatic compounds uch as benzene or naphthalene">benzene.html" ;"title="uch as benzene">uch as benzene or naphthalene] by conversion of an even number of –CH= group ...

. The Glycerol 3-phosphate shuttle is an emergency back-up system to supply neuron#Neurotransmitter, neurons' demand of energy.

Dephosphorylation

Glycerol-3-phosphate was found to be a substrate for the enzyme phosphoglycolate phosphatase (PGP, or G3PP) in mammals in 2015. G3PP activity has subsequently been suggested to have a regulatory role in central metabolism and stress response.

Glycerol 1-phosphate

Glycerol 1-phosphate ''sn''-Glycerol 1-phosphate is the conjugate base of a phosphoric ester of glycerol. It is a component of ether lipids, which are common for archaea. Biosynthesis and metabolism Glycerol 1-phosphate is synthesized by reducing dihydroxyaceton ...

, sometimes called as -glycerol 3-phosphate, is the

enantiomer In chemistry, an enantiomer ( /ɪˈnænti.əmər, ɛ-, -oʊ-/ ''ih-NAN-tee-ə-mər''; from Ancient Greek ἐνάντιος ''(enántios)'' 'opposite', and μέρος ''(méros)'' 'part') – also called optical isomer, antipode, or optical anti ...

of glycerol 3-phosphate. Most higher organisms use the 3-phosphate, or -configuration, for glycerolipid backbone. The 1-phosphate is specifically found in archeal lipids.

Notes

{{DEFAULTSORT:Glycerol 3-Phosphate Vicinal diols Organophosphates Glycerol esters Phosphate esters