Diglyceride

A diglyceride, more correctly known as a diacylglycerol, is a glyceride consisting of two ester linkages. Shown on the right is 1-fatty acids attached at 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.

Function

Activate PKC

In biochemical signaling, diacylglycerol (DAG) functions as a protein kinase C (PKC). However, for DAG to activate PKC, there needs to be a cytosolic increase in calcium ions, which is accomplished by IP3. Diacylglycerol can be mimicked by phorbol esters.

Further reading: function of PKC

Other

In addition to activating PKC, diacylglycerol has a number of other functions in the cell:

• a source for prostaglandins
• a precursor of the endocannabinoid 2-arachidonoylglycerol
• an activator of a subfamily of TRPC (Transient Receptor Potential Canonical) cation channels, TRPC3/6/7.

Metabolism

Synthesis of diacylglycerol begins with glycerol-3-phosphate, which is derived primarily from 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.

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. ^[1]

Additional images

References