Phosphatidylserine and Related Lipids

Although phosphatidylserine or 1,2-diacyl-sn-glycero-3-phospho-L-serine is distributed widely among animals, plants and microorganisms, it is usually less than 10% of the total phospholipids, the greatest concentration being in myelin from brain tissue. However, it may comprise 10 to 20 mol% of the total phospholipid in the plasma membrane and endoplasmic reticulum of the cell. In yeasts, such as S. cerivisiae, it is a minor component of most other cellular organelles other than the plasma membrane, where it can amount to more than 30% of the total lipids. In most bacteria, it is a minor membrane lipid, although it is important as an intermediate in phosphatidylethanolamine biosynthesis. The 1-octadecanoyl-2-docosahexaenoyl molecular species, which may be especially important in brain tissue, is illustrated here.