13diacilglicerol

13diacilglicerol, also known as 1,3-diacylglycerol, is a diacylglycerol molecule in which two fatty acyl chains are esterified to the glycerol backbone at the 1 and 3 positions, leaving a free hydroxyl group at the 2 position. This distinguishes it from 1,2-diacylglycerol, another common diacylglycerol regioisomer. The fatty acid chains vary in length and degree of unsaturation, giving rise to a broad range of DAG species.

In biochemistry, 1,3-diacylglycerol is an intermediate in glycerolipid metabolism. It can be produced by the hydrolysis of phospholipids or triacylglycerols, and phospholipase C–type reactions on phosphatidyl lipids can generate DAG as a product alongside head-group moieties. In cellular membranes, diacylglycerols serve as transient intermediates and signaling molecules, linking lipid metabolism to signal transduction.

A notable function of diacylglycerol is its role as a second messenger that activates certain isoforms of protein kinase C (PKC) and related signaling proteins. The potency and outcome of DAG signaling depend on the specific acyl chains and the glycerol backbone’s regioisomerism. DAG can also act as a substrate for diacylglycerol acyltransferase, which converts it to triacylglycerol for storage.

Beyond its biological role, diacylglycerols are studied for their metabolic importance and, in some contexts, for industrial applications as intermediates in lipid synthesis and as emulsifying agents.