12diacilglicerol

12-diacilglicerol, also called 1,2-diacilglicerol, is a diacylglycerol comprising a glycerol backbone with two fatty acid chains esterified at the sn-1 and sn-2 positions, leaving a free hydroxyl at the sn-3 position. The fatty acyl chains vary in length and degree of saturation, giving many possible species within this class.

In biological membranes, diacylglycerols are important intermediates in lipid metabolism and can function as signaling molecules. One major pathway generates DAG by phospholipase C cleavage of phosphatidylinositol bisphosphate (PIP2), producing DAG and inositol trisphosphate (IP3). Diacylglycerol can also arise from the dephosphorylation of phosphatidic acid or be formed during triglyceride turnover. DAG acts as a second messenger by associating with proteins that contain C1 domains, notably conventional and novel protein kinase C isoforms, thereby influencing various phosphorylation cascades and cellular responses.

A key metabolic role of DAG is as a precursor for triacylglycerol (triglyceride) synthesis; diacylglycerol acyltransferase adds a third fatty acid to form the triglyceride backbone. DAG can also be converted to phosphatidic acid by kinases, linking it to broader phospholipid remodeling processes.

DAG species, including 12-diacilglicerol, are analyzed in lipidomics to study membrane composition and signaling pathways. Their exact biological effects depend on acyl chain length and saturation as well as cellular context.