6 - Phosphatidylserine: Biology, Technologies, and Applications

Abstract

Like other glycerophospholipids, Phosphatidylserine (PS) exists as one of the components of the bilayer membrane of a cell. Though not as abundant as phosphatidylcholine (PC) and phosphatidylethanolamine (PE or cepharin), PS is one of the most important phospholipids, both from biological function and dietary nutrition points of view. PS is located asymmetrically in the cell membrane and mostly in the inner leaflet of the cell. Besides maintaining membrane integrity, it is also involved in various cell activities through binding to and activating on several classes of enzymes and supplying a negatively charged surface in order to recruit positively charged molecules such as proteins. As a member of the glycerophospholipid class, the PS molecule has a glycerol moiety esterified by fatty acids at the first and second positions of the glycerol molecule, and the head group at the third position is the amino acid serine esterified to phosphate. Therefore, it is negatively charged under physiological conditions, unlike PC and PE that are zwitterionic. This physical property is very important for PS as it lays the foundation for the biological functions of PS within the cell. In recent years, with the help of emerging technologies, elucidation of the biological function of PS has made great progress. This chapter focuses on the new findings about the functionality of this important phospholipid, including the authors' works, from a practical point of view.