Phosphatidylethanolamine

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.

Phosphatidylethanolamines are found in all living cells, composing 25% of all phospholipids. In human physiology, they are found particularly in nervous tissue such as the white matter of brain, nerves, neural tissue, and in spinal cord, where they make up 45% of all phospholipids.

PEs play a role in membrane fusion and in disassembly of the contractile ring during cytokinesis in cell division. Additionally, it is thought that PE regulates membrane curvature. PE acts as an important precursor, substrate, or donor in several biological pathways.

As a polar head group, PE creates a more viscous lipid membrane compared to phosphatidylcholine (PC). For example, the melting temperature of di-oleoyl-PE is -16 °C while the melting temperature of di-oleoyl-PC is -20 °C. If the lipids had two palmitoyl chains, PE would melt at 63°C while PC would melt already at 41 °C. Lower melting temperatures correspond, in a simplistic view, to more fluid membranes.

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