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Diglyceride

 

 
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Diglyceride
 
 
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A diglyceride, or a diacylglycerol (DAG), is a glyceride
Glyceride

Glycerides, more correctly known as acylglycerols, are esters formed from glycerol and fatty acids.Glycerol has three hydroxyl functional groups, which can be esterified with one, two, or three fatty acids to form monoglycerides, diglycerides, and triglycerides....
 consisting of two fatty acid
Fatty acid

In chemistry, especially biochemistry, a fatty acid is a carboxylic acid often with a long unbranched aliphatic tail , which is either saturation or Unsaturated compound....
 chains covalently bonded
Covalent bond

A covalent bond is a form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms, or between atoms and other covalent bonds....
 to a glycerol
Glycerol

Glycerol is a chemical compound also commonly called glycerin or glycerine. It is a colorless, odorless, Viscosity liquid that is widely used in pharmaceutical formulations....
 molecule through ester
Ester

An ester is an often Aroma compound organic chemistry or partially organic compound formed by the reaction between an acid and an alcohol or aromatic alcohol with the elimination of water....
 linkages. One example, shown on the right, is 1-palmitoyl-2-oleoyl-glycerol, which contains side-chains derived from palmitic acid
Palmitic acid

Palmitic acid,CH314COOH or hexadecanoic acid in IUPAC nomenclature, is one of the most common saturated fatty acids found in animals and plants....
 and oleic acid
Oleic acid

Oleic acid is a monounsaturated omega-9 fatty acid fatty acid found in various animal and vegetable sources. It has the formula C18H34O2 ....
. Diacylglycerols can also have many different combinations of fatty acids attached at both the C-1 and C-2 positions.

- and diacylglycerols are common food additives used to blend together certain ingredients, such as oil and water, which would not otherwise blend well.

The commercial source may be either animal (cow- or hog-derived) or vegetable, derived primarily from soy bean and canola oil.






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A diglyceride, or a diacylglycerol (DAG), is a glyceride
Glyceride

Glycerides, more correctly known as acylglycerols, are esters formed from glycerol and fatty acids.Glycerol has three hydroxyl functional groups, which can be esterified with one, two, or three fatty acids to form monoglycerides, diglycerides, and triglycerides....
 consisting of two fatty acid
Fatty acid

In chemistry, especially biochemistry, a fatty acid is a carboxylic acid often with a long unbranched aliphatic tail , which is either saturation or Unsaturated compound....
 chains covalently bonded
Covalent bond

A covalent bond is a form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms, or between atoms and other covalent bonds....
 to a glycerol
Glycerol

Glycerol is a chemical compound also commonly called glycerin or glycerine. It is a colorless, odorless, Viscosity liquid that is widely used in pharmaceutical formulations....
 molecule through ester
Ester

An ester is an often Aroma compound organic chemistry or partially organic compound formed by the reaction between an acid and an alcohol or aromatic alcohol with the elimination of water....
 linkages. One example, shown on the right, is 1-palmitoyl-2-oleoyl-glycerol, which contains side-chains derived from palmitic acid
Palmitic acid

Palmitic acid,CH314COOH or hexadecanoic acid in IUPAC nomenclature, is one of the most common saturated fatty acids found in animals and plants....
 and oleic acid
Oleic acid

Oleic acid is a monounsaturated omega-9 fatty acid fatty acid found in various animal and vegetable sources. It has the formula C18H34O2 ....
. Diacylglycerols can also have many different combinations of fatty acids attached at both the C-1 and C-2 positions.

Food additive

Mono- and diacylglycerols are common food additives used to blend together certain ingredients, such as oil and water, which would not otherwise blend well.

The commercial source may be either animal (cow- or hog-derived) or vegetable, derived primarily from soy bean and canola oil. They may also be synthetically produced. They are often found in bakery products, beverages, ice cream, chewing gum, shortening, whipped toppings, margarine, and confections.

Biological functions


PKC activation

In biochemical signaling, diacylglycerol functions as a second messenger signaling lipid
Lipid signaling

Lipid signaling, broadly defined, refers to any biological signaling event involving a lipid messenger that binds and activates a Receptor . Lipid signaling is thought to be qualitatively different from other classical signaling paradigms because lipids can freely diffuse through membranes....
, and is a product of the hydrolysis of the phospholipid PIP2
PIP2

PIP2, or phosphatidylinositol biphosphate, is a general term that refers to the products obtained by cleavage of PIP3.PIP2 is a substrate for cleavage with phospholipase C , a membrane-bound enzyme activated through protein receptors like a1 adrenergic receptors....
 (phosphatidyl inositol-bisphosphate) by the enzyme
Enzyme

Enzymes are biomolecules that catalysis chemical reactions. Almost all enzymes are proteins. In enzymatic reactions, the molecules at the beginning of the process are called Substrate , and the enzyme converts them into different molecules, the products....
 phospholipase
Phospholipase

A phospholipase is an enzyme that hydrolyzes phospholipids into fatty acids and other lipophilic substances. There are four major classes, termed A, B, C and D distinguished by what type of reaction they catalyze:...
 C (PLC
Phospholipase C

Phosphoinositide phospholipase C is a family of eukaryotic intracellular enzymes that play an important role in signal transduction processes....
) (a membrane
Cell membrane

The cell membrane is the interface between the cellular machinery inside the cell and the fluid outside.It is a semipermeable lipid bilayer found in all cell ....
-bound enzyme) that, through the same reaction, produces inositol triphosphate
Inositol triphosphate

Inositol trisphosphate or inositol 1,4,5-trisphosphate , together with diglyceride, is a secondary messenger molecule used in signal transduction in cell s....
 (IP3). Although inositol triphosphate (IP3) diffuses into the cytosol
Cytosol

The cytosol or intracellular fluid is the liquid found inside cell . In eukaryotes this liquid is separated by cell membranes from the contents of the organelles suspended in the cytosol, such as the mitochondrial matrix inside the mitochondrion....
, diacylglycerol (DAG) remains within the plasma membrane, due to its hydrophobic
Hydrophobe

In chemistry, hydrophobicity refers to the physical property of a molecule that is repelled from a mass of water.Hydrophobic molecules tend to be non-polar and thus prefer other neutral molecules and nonpolar solvents....
 properties. IP3 stimulates the release of calcium ions from the smooth endoplasmic reticulum, whereas DAG is a physiological activator of protein kinase C
Protein kinase C

Protein kinase C is a family of protein kinases consisting of ~10 isozymes. They are divided into three subfamilies, based on their second messenger requirements: conventional , novel, and atypical....
 (PKC). The production of DAG in the membrane facilitates translocation of PKC from the cytosol to the plasma membrane.

Diacylglycerol can be mimicked by the tumor-promoting compounds phorbol esters.

Other

In addition to activating PKC, diacylglycerol has a number of other functions in the cell
Cell (biology)

The cell is the structural and functional unit of all known Life organisms. It is the smallest unit of an organism that is classified as living, and is often called the building bricks of life....
:

  • a source for prostaglandin
    Prostaglandin

    A prostaglandin is any member of a group of lipid compounds that are derived enzymatically from fatty acids and have important functions in the animal body....
    s
  • a precursor of the endocannabinoid 2-arachidonoylglycerol
    2-Arachidonoylglycerol

    2-Arachidonoylglycerol , is an endocannabinoid, an endogenous agonist of the CB1 receptor.It is an ester formed from the omega-6 fatty acid arachidonic acid and glycerol....
  • an activator of a subfamily of TRPC
    TRPC

    TRPC is a family of transient receptor potential ion channel in animals.TRPC channels form the subfamily of channels in human most closely related to drosophila TRP channels....
     (Transient Receptor Potential Canonical) cation channels, TRPC3/6/7.


Metabolism

Synthesis of diacylglycerol begins with glycerol-3-phosphate, which is derived primarily from dihydroxyacetone phosphate, a product of glycolysis
Glycolysis

Glycolysis is the metabolic pathway that converts glucose, C6H12O6, into pyruvate, C3H5O3-....
 (usually in the cytoplasm of liver or adipose tissue cells). Glycerol-3-phosphate is first acylated
Acylation

In chemistry, acylation is the process of adding an acyl group to a compound. The compound providing the acyl group is called the acylating agent....
 with acyl-coenzyme A (acyl-CoA) to form lysophosphatidic acid
Lysophosphatidic acid

Lysophosphatidic acid is a phospholipid derivative that acts as a potent lipid signaling molecule. There are a number of potential routes to its biosynthesis, but the most well-characterized is by the action of a lysophospholipase D called autotaxin, which removes the choline group from lysophosphatidylcholine....
, which is then acylated with another molecule of acyl-CoA to yield phosphatidic acid. Phosphatidic acid is then de-phosphorylated to form diacylglycerol.

Diacylglycerol is a precursor to triacylglycerol (triglyceride), which is formed in the addition of a third fatty acid to the diacylglycerol under the catalysis of diglyceride acyltransferase
Diglyceride acyltransferase

Diglyceride acyltransferase , DGAT, catalyzes the formation of triglycerides from diacylglycerol and Acyl-CoA. The reaction catalyzed by DGAT is considered the terminal and only committed step in triglyceride synthesis and to be essential for the formation of adipose tissue....
.

Since diacylglycerol is synthesized via phosphatidic acid, it will usually contain a saturated fatty acid at the C-1 position on the glycerol moiety and an unsaturated fatty acid at the C-2 position.

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