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

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 () is a simple triol compound. It is a colorless, odorless, sweet-tasting, viscous liquid. The glycerol backbone is found in lipids known as glycerides. It is also widely used as a sweetener in the food industry and as a humectant in pha ...

. It is a component of bacterial and eukaryotic

glycerophospholipid Glycerophospholipids or phosphoglycerides are glycerol-based phospholipids. They are the main component of biological membranes in eukaryotic cells. They are a type of lipid, of which its composition affects membrane structure and properties. T ...

s. 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 pyruvic acid, pyruvate and, in most organisms, occurs in the liquid part of cells (the cytosol). The Thermodynamic free energy, free energy released in this process is used to form ...

. 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 over 500 amino acids exist in nature, by far the most important are the Proteinogenic amino acid, 22 α-amino acids incorporated into p ...

and

citric acid cycle The citric acid cycle—also known as the Krebs cycle, Szent–Györgyi–Krebs cycle, or TCA cycle (tricarboxylic acid cycle)—is a series of chemical reaction, biochemical reactions that release the energy stored in nutrients through acetyl-Co ...

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 biochemistry, phosphorylation is described as the "transfer of a phosphate group" from a donor to an acceptor. A common phosphorylating agent (phosphate donor) is ATP and a common family of acceptor are alcohols: : This equation can be writ ...

, which is generated by hydrolysis of

fat In nutrition science, nutrition, biology, and chemistry, fat usually means any ester of fatty acids, or a mixture of such chemical compound, compounds, most commonly those that occur in living beings or in food. The term often refers specif ...

s. This esterification is catalyzed by glycerol kinase. : Glycerin Skelett2

+ ATP →

+ ADP

Metabolism and biological function

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

glycerolipid Lipids are a broad group of organic compounds which include fats, waxes, sterols, fat-soluble vitamins (such as vitamins Vitamin A, A, Vitamin D, D, Vitamin E, E and Vitamin K, K), monoglycerides, diglycerides, phospholipids, and others. The fu ...

s. In

eukaryotes The eukaryotes ( ) constitute the domain of Eukaryota or Eukarya, organisms whose cells have a membrane-bound nucleus. All animals, plants, fungi, seaweeds, and many unicellular organisms are eukaryotes. They constitute a major group of ...

, it is first acylated on its ''sn''-1 position by an ER- or mitochondrial membrane enzyme, glycerol-3-phosphate O-acyltransferase. A second acyl group is subsequently installed on the ''sn''-2 position making phosphatidic acids. : Glycerin-3-phosphat Skelett

Acyl-CoA Acyl-CoA is a group of coenzyme A, CoA-based coenzymes that metabolize carboxylic acids. Fatty acyl-CoA's are susceptible to beta oxidation, forming, ultimately, acetyl-CoA. The acetyl-CoA enters the citric acid cycle, eventually forming several e ...

→ Lysophosphatidic acid + CoA Glycerol-1-phosphatase catalyzes the hydrolysis of glycerol 3-phosphate to regenerate

, allowing glycerol fermentation to produce glycerol from

glucose Glucose is a sugar with the Chemical formula#Molecular formula, molecular formula , which is often abbreviated as Glc. It is overall the most abundant monosaccharide, a subcategory of carbohydrates. It is mainly made by plants and most algae d ...

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 ade ...

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 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 benzene.html" ;"title="uch as benzene">uch as benzene or naphthalene] by conversion of an even number of –CH= groups into –C(=O)– groups with ...

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

enantiomer In chemistry, an enantiomer (Help:IPA/English, /ɪˈnænti.əmər, ɛ-, -oʊ-/ Help:Pronunciation respelling key, ''ih-NAN-tee-ə-mər''), also known as an optical isomer, antipode, or optical antipode, is one of a pair of molecular entities whi ...

of glycerol 3-phosphate. Eukaryotes use the 3-phosphate, or -configuration, for glycerolipid backbone. The 1-phosphate is specifically found in archaeal lipids.

Notes

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