Phosphatidyl

Phosphatidyl refers to a class of glycerophospholipids characterized by a diacylglycerol backbone linked to a phosphate group, which in turn is bound to a polar head group. The common arrangement places two fatty acyl chains at the sn-1 and sn-2 positions of glycerol, while the phosphate at the sn-3 position is esterified to a head group such as choline, ethanolamine, serine, inositol, or glycerol. When the head group is choline, the molecule is phosphatidylcholine; when it is ethanolamine, phosphatidylethanolamine; serine yields phosphatidylserine; inositol yields phosphatidylinositol. The general structural motif is thus diacylglycerol-3-phosphate with a head group attached via a phosphate ester, giving an amphipathic molecule essential for biological membranes.

In biology, phosphatidyl derivatives are major components of cell membranes, contributing to membrane fluidity, curvature, and fusogenic properties. They also participate in signaling pathways; for instance, phosphatidylinositol and its phosphorylated derivatives (phosphatidylinositol phosphates) are key mediators of intracellular signaling. Phosphatidylcholine and phosphatidylethanolamine are abundant in eukaryotic membranes and play roles in membrane structure and protein interactions.

Biosynthesis proceeds from diacylglycerol to phosphatidic acid and then to various phosphatidyl lipids via head-group transfer reactions, often involving CDP-activated donors. Remodeling and acyl-chain composition are regulated by acyltransferases and phospholipases, influencing membrane properties and signaling.