Phosphatidylethanolamines (sometimes abbreviated PE) are a class of phospholipids found in biological membranes. They are synthesized by the addition of CDP-ethanolamine to diglycerides, releasing CMP. S-Adenosyl methionine can subsequently methylate the amine of phosphatidylethanolamines to yield phosphatidylcholines. It can mainly be found in the inner (cytoplasmic) leaflet of the lipid bilayer.