phosphatecholine

Phosphocholine is a zwitterionic molecule consisting of a choline moiety linked to a phosphate group through a phosphoester bond. It forms the hydrophilic headgroup of several membrane lipids, most notably phosphatidylcholine, and also appears as the headgroup of sphingomyelin in many cell membranes. The presence of the phosphocholine headgroup contributes to the surface charge and amphipathic properties of membranes.

In metabolism, phosphocholine is an intermediate in the biosynthesis of phosphatidylcholine via the Kennedy pathway. Choline is first phosphorylated by choline kinase to produce phosphocholine, which is then converted to CDP-choline and ultimately transferred onto diacylglycerol to form phosphatidylcholine. Phosphocholine can also be generated by hydrolysis of phosphatidylcholine or glycerophosphocholine and can be dephosphorylated to free choline by phosphatases.

Physiological relevance: As a component of membrane lipids, phosphocholine participates in membrane structure, signaling, and lipid metabolism. Because choline derivatives are essential for methyl group metabolism and neurotransmitter synthesis, phosphocholine is connected to broader nutritional and metabolic pathways. Dietary choline intake and liver function influence the availability of choline-derived lipids in membranes.

See also: phosphatidylcholine; sphingomyelin; choline metabolism.