Plasmaloglyceriden

Plasmalogens are a class of ether lipids that are abundant in animal tissues, particularly in the nervous system, heart, and immune cells. They are characterized by a vinyl ether or alkyl ether linkage at the sn-1 position of the glycerol backbone, instead of the typical ester linkage found in most phospholipids. The sn-2 position is esterified with a fatty acid, and the sn-3 position carries a phosphorylcholine, phosphorylethanolamine, or other head group.

The biosynthesis of plasmalogens begins with the reduction of dihydroxyacetone phosphate to glycerol-3-phosphate. An acyl group is then esterified to the sn-1 position, followed by the addition of an alkyl group at the sn-1 position via an ether linkage. This is followed by deacylation at the sn-2 position and re-acylation with a fatty acid. Finally, a polar head group is attached to the sn-3 position.

Plasmalogens are thought to play a role in various cellular functions, including membrane structure, antioxidant defense, and signal transduction. Their unique ether linkage makes them more resistant to hydrolysis compared to ester-linked lipids, potentially contributing to their protective functions. Deficiency or altered levels of plasmalogens have been associated with certain neurological disorders and other diseases, although their precise roles in these conditions are still under investigation.