Lecithin, (egg)/ml, 1 ml chloroform

This product is a high purity phosphatidylcholine (PC) containing a natural mixture of fatty acids acylated to the sn-1 and sn- 2 positions. PC is a major component of biological membranes, especially in the outer leaflet, often composing almost 50% of the total phospholipids.{139} It is a vital component in membrane bilayers and is the main phospholipid circulating in plasma. PC plays an important role in membrane-mediated cell signaling by generating diacylglycerols and phospholipids.{50622} Phospholipase D is an enzyme that cleaves off the choline head group, converting PC to phosphatidic acid, while phospholipase C cleaves off the phosphate group leaving diacylglycerol. PC is the biosynthetic precursor of sphingomyelin, phosphatidylethanolamine, lyso-phosphatidylcholine, and platelet-activating factor. The choline headgroup is an essential nutrient in animals although it can be synthesized by methylating phosphatidylethanolamine to phosphatidylcholine and then cleaving the headgroup with phospholipase D.{29456} Tumor cells appear to have increased synthesis of PC and this may be a potential target for cancer therapy. Another function of PC is the activation of enzymes such as the enzyme 3- hydroxybutyrate dehydrogenase which must be bound to phosphatidylcholine before it can function optimally.