![]() The phosphatidylserine decarboxylation pathway is the main source of synthesis for phosphatidylethanolamine in the membranes of the mitochondria. Phosphatidylserine decarboxylase is the enzyme that is used to decarboxylate phosphatidylserine in the first pathway. The phosphatidylserine decarboxylation pathway and the cytidine diphosphate-ethanolamine pathways are used to synthesize phosphatidylethanolamine. ![]() The two fatty acids may be identical or different, and are usually found in positions 1,2 (less commonly in positions 1,3). Whereas the phosphate group is combined with choline in phosphatidylcholine, it is combined with ethanolamine in phosphatidylethanolamine. Structure Īs a lecithin, phosphatidylethanolamine consists of a combination of glycerol esterified with two fatty acids and phosphoric acid. Phosphatidylethanolamine also enables bacterial multidrug transporters to function properly and allows the formation of intermediates that are needed for the transporters to properly open and close. When phosphatidylethanolamine is not present, the transport proteins have incorrect tertiary structures and do not function correctly. It acts as a 'chaperone' to help the membrane proteins correctly fold their tertiary structures so that they can function properly. Phosphatidylethanolamine plays a role in the assembly of lactose permease and other membrane proteins. coli, phosphatidylethanolamine play a role in supporting lactose permeases active transport of lactose into the cell, and may play a role in other transport systems as well. One of the primary roles for phosphatidylethanolamine in bacterial membranes is to spread out the negative charge caused by anionic membrane phospholipids. Where phosphatidylcholine is the principal phospholipid in animals, phosphatidylethanolamine is the principal one in bacteria. The synthesis of endocannabinoid anandamide is performed from the phosphatidylethanolamine by the successive action of 2 enzymes, the N- acetyltransferase and phospholipase-D. Phosphatidylethanolamine is also thought to play a role in blood clotting, as it works with phosphatidylserine to increase the rate of thrombin formation by promoting binding to factor V and factor X, two proteins which catalyze the formation of thrombin from prothrombin. Phosphatidylethanolamine has also shown to be able to propagate infectious prions without the assistance of any proteins or nucleic acids, which is a unique characteristic of it. This is because vesicles for secretion of very low-density lipoproteins coming off of the Golgi apparatus have a significantly higher phosphatidylethanolamine concentration when compared to other vesicles containing very low-density lipoproteins. Additionally, phosphatidylethanolamine plays a role in the secretion of lipoproteins in the liver. When blood flow to the heart is restricted, the asymmetrical distribution of phosphatidylethanolamine between membrane leaflets is disrupted, and as a result the membrane is disrupted. In humans, metabolism of phosphatidylethanolamine is thought to be important in the heart. Lower melting temperatures correspond, in a simplistic view, to more fluid membranes. If the lipids had two palmitoyl chains, phosphatidylethanolamine would melt at 63 ☌ while phosphatidylcholine would melt already at 41 ☌. For example, the melting temperature of di-oleoyl-phosphatidylethanolamine is -16 ☌ while the melting temperature of di-oleoyl-phosphatidylcholine is -20 ☌. Īs a polar head group, phosphatidylethanolamine creates a more viscous lipid membrane compared to phosphatidylcholine. Phosphatidylethanolamine is an important precursor, substrate, or donor in several biological pathways. Additionally, it is thought that phosphatidylethanolamine regulates membrane curvature. Phosphatidylethanolamines play a role in membrane fusion and in disassembly of the contractile ring during cytokinesis in cell division. 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. Phosphatidylethanolamines are found in all living cells, composing 25% of all phospholipids. There are multiple factors that lead to membrane fluidity.The major membrane lipids: phosphatidylcholine (PtdCho) phosphatidylethanolamine (PtdEtn) phosphatidylinositol (PtdIns) phosphatidylserine (PtdSer).
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