fosfatidilkolin

Fosfatidilkolin, also known as phosphatidylcholine (PC), is a glycerophospholipid that constitutes a major component of biological membranes. It is an amphipathic molecule with a hydrophilic choline-containing head and two hydrophobic fatty acid tails, enabling it to form bilayers and lipoprotein particles.

In PC, a glycerol backbone bears two fatty acids at the sn-1 and sn-2 positions and a phosphate group linked to choline at the sn-3 position. The choline head group is a quaternary ammonium, giving the molecule an overall zwitterionic character at physiological pH.

Phosphatidylcholine is abundant in cell membranes and in circulating lipoproteins. It contributes to membrane integrity and fluidity, participates in lipid transport, and serves as a reservoir for choline, which can be converted to acetylcholine or to methyl groups via betaine. PC is found in many foods, notably soy lecithin and egg yolk, and is widely used as an emulsifier in the food industry (often labeled as lecithin, E322).

Biosynthesis occurs predominantly via the CDP-choline pathway (Kennedy pathway), wherein choline is activated to CDP-choline and then combined with diacylglycerol to form phosphatidylcholine. An alternative route involves sequential methylation of phosphatidylethanolamine to phosphatidylcholine.

In nutrition and medicine, phosphatidylcholine is used as a dietary supplement and is studied for potential effects on liver health and lipid metabolism. Evidence for therapeutic benefits remains mixed, and use should follow clinical guidance.