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Phosphatidylethanolamine

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Biosynthesis of various phospholipids (including phosphatidylethanolamine) in bacteria

Phosphatidylethanolamine(PE) is a class ofphospholipidsfound inbiological membranes.[1]They are synthesized by the addition ofcytidine diphosphate-ethanolaminetodiglycerides,releasingcytidine monophosphate.S-Adenosyl methioninecan subsequentlymethylatetheamineof phosphatidylethanolamines to yieldphosphatidylcholines.

Function[edit]

The majormembrane lipids:phosphatidylcholine(PtdCho); phosphatidylethanolamine (PtdEtn);phosphatidylinositol(PtdIns);phosphatidylserine(PtdSer).

In cells[edit]

Phosphatidylethanolamines are found in all living cells, composing 25% of all phospholipids. In human physiology, they are found particularly in nervous tissue such as thewhite matterofbrain,nerves, neural tissue, and inspinal cord,where they make up 45% of all phospholipids.[2]

Phosphatidylethanolamines play a role inmembrane fusionand in disassembly of thecontractile ringduringcytokinesisincell division.[3]Additionally, it is thought that phosphatidylethanolamine regulatesmembrane curvature.Phosphatidylethanolamine is an important precursor,substrate,or donor in several biological pathways.[2]

As a polar head group, phosphatidylethanolamine creates a more viscous lipid membrane compared tophosphatidylcholine.For example, the melting temperature of di-oleoyl-phosphatidylethanolamine is -16 °C while the melting temperature of di-oleoyl-phosphatidylcholine is -20 °C. If the lipids had two palmitoyl chains, phosphatidylethanolamine would melt at 63 °C while phosphatidylcholine would melt already at 41 °C.[4]Lower melting temperatures correspond, in a simplistic view, to more fluid membranes.

In humans[edit]

In humans, metabolism of phosphatidylethanolamine is thought to be important in the heart. 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. Additionally, phosphatidylethanolamine plays a role in the secretion oflipoproteinsin the liver. This is because vesicles for secretion ofvery low-density lipoproteinscoming off of theGolgi apparatushave a significantly higher phosphatidylethanolamine concentration when compared to other vesicles containing very low-density lipoproteins.[5]Phosphatidylethanolamine has also shown to be able to propagate infectiousprionswithout the assistance of anyproteinsornucleic acids,which is a unique characteristic of it.[6]Phosphatidylethanolamine is also thought to play a role in blood clotting, as it works withphosphatidylserineto increase the rate ofthrombinformation by promoting binding tofactor Vandfactor X,two proteins which catalyze the formation of thrombin fromprothrombin.[7]The synthesis of endocannabinoidanandamideis performed from the phosphatidylethanolamine by the successive action of two enzymes,N-acetyltransferaseandphospholipase-D.[8]

In bacteria[edit]

Where phosphatidylcholine is the principalphospholipidin animals, phosphatidylethanolamine is the principal one inbacteria.One of the primary roles for phosphatidylethanolamine in bacterial membranes is to spread out the negative charge caused byanionicmembranephospholipids.In the bacteriumE. coli,phosphatidylethanolamine play a role in supportinglactose permeasesactive transport of lactose into the cell, and may play a role in other transport systems as well. Phosphatidylethanolamine plays a role in the assembly of lactose permease and other membrane proteins. It acts as a 'chaperone' to help the membrane proteins correctly fold theirtertiary structuresso that they can function properly. When phosphatidylethanolamine is not present, the transport proteins have incorrect tertiary structures and do not function correctly.[9]

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.[10]

Structure[edit]

Ethanolamine

As alecithin,phosphatidylethanolamine consists of a combination ofglycerolesterified with twofatty acidsandphosphoric acid.Whereas the phosphate group is combined withcholinein phosphatidylcholine, it is combined withethanolaminein phosphatidylethanolamine. The two fatty acids may be identical or different, and are usually found in positions 1,2 (less commonly in positions 1,3).

Synthesis[edit]

Thephosphatidylserinedecarboxylationpathway and thecytidine diphosphate-ethanolaminepathways are used to synthesize phosphatidylethanolamine.Phosphatidylserine decarboxylaseis the enzyme that is used to decarboxylate phosphatidylserine in the first pathway. The phosphatidylserine decarboxylation pathway is the main source of synthesis for phosphatidylethanolamine in the membranes of themitochondria.Phosphatidylethanolamine produced in the mitochondrial membrane is also transported throughout the cell to other membranes for use. In a process that mirrorsphosphatidylcholinesynthesis, phosphatidylethanolamine is also made via the cytidine diphosphate-ethanolamine pathway, usingethanolamineas the substrate. Through several steps taking place in both thecytosolandendoplasmic reticulum,the synthesis pathway yields the end product of phosphatidylethanolamine.[11]Phosphatidylethanolamine is also found abundantly in soy or egg lecithin and is produced commercially using chromatographic separation.

Regulation[edit]

Synthesis of phosphatidylethanolamine through thephosphatidylserinedecarboxylationpathway occurs rapidly in theinner mitochondrial membrane.However, phosphatidylserine is made in theendoplasmic reticulum.Because of this, the transport of phosphatidylserine from the endoplasmic reticulum to the mitochondrial membrane and then to the inner mitochondrial membrane limits the rate of synthesis via this pathway. The mechanism for this transport is currently unknown but may play a role in the regulation of the rate of synthesis in this pathway.[12]

Presence in food, health issues[edit]

Phosphatidylethanolamines in food break down to form phosphatidylethanolamine-linkedAmadori productsas a part of theMaillard reaction.[13]These products acceleratemembranelipidperoxidation,causingoxidative stressto cells that come in contact with them.[14]Oxidative stress is known to cause food deterioration and several diseases. Significant levels of Amadori-phosphatidylethanolamine products have been found in a wide variety of foods such aschocolate,soybean milk,infant formula,and otherprocessed foods.The levels of Amadori-phosphatidylethanolamine products are higher in foods with high lipid and sugar concentrations that have high temperatures in processing.[13]Additional studies have found that Amadori-phosphatidylethanolamine may play a role invascular disease,[15]act as the mechanism by whichdiabetescan increase the incidence ofcancer,[16]and potentially play a role in other diseases as well. Amadori-phosphatidylethanolamine has a higherplasmaconcentrationin diabetes patients than healthy people, indicating it may play a role in the development of the disease or be a product of the disease.[17]

See also[edit]

References[edit]

  1. ^Wellner, Niels; Diep, Thi Ai; Janfelt, Christian; Hansen, Harald Severin (2012). "N-acylation of phosphatidylethanolamine and its biological functions in mammals".Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids.1831(3): 652–62.doi:10.1016/j.bbalip.2012.08.019.PMID23000428.
  2. ^abVance, Jean E.; Tasseva, Guergana (2012). "Formation and function of phosphatidylserine and phosphatidylethanolamine in mammalian cells".Biochimica et Biophysica Acta (BBA) - Molecular and Cell Biology of Lipids.1831(3): 543–54.doi:10.1016/j.bbalip.2012.08.016.PMID22960354.
  3. ^Emoto, K.; Kobayashi, T; Yamaji, A; Aizawa, H; Yahara, I; Inoue, K; Umeda, M (1996)."Redistribution of phosphatidylethanolamine at the cleavage furrow of dividing cells during cytokinesis".Proceedings of the National Academy of Sciences.93(23): 12867–72.Bibcode:1996PNAS...9312867E.doi:10.1073/pnas.93.23.12867.JSTOR40713.PMC24012.PMID8917511.
  4. ^See references in Wan et al. Biochemistry 47 2008[verification needed]
  5. ^Vance, J. E. (2008)."Thematic Review Series: Glycerolipids. Phosphatidylserine and phosphatidylethanolamine in mammalian cells: Two metabolically related aminophospholipids".The Journal of Lipid Research.49(7): 1377–87.doi:10.1194/jlr.R700020-JLR200.PMID18204094.
  6. ^Deleault, N. R.; Piro, J. R.; Walsh, D. J.; Wang, F.; Ma, J.; Geoghegan, J. C.; Supattapone, S. (2012)."Isolation of phosphatidylethanolamine as a solitary cofactor for prion formation in the absence of nucleic acids".Proceedings of the National Academy of Sciences.109(22): 8546–51.Bibcode:2012PNAS..109.8546D.doi:10.1073/pnas.1204498109.PMC3365173.PMID22586108.
  7. ^Majumder, R.; Liang, X.; Quinn-Allen, M. A.; Kane, W. H.; Lentz, B. R. (2011)."Modulation of Prothrombinase Assembly and Activity by Phosphatidylethanolamine".Journal of Biological Chemistry.286(41): 35535–42.doi:10.1074/jbc.M111.260141.PMC3195639.PMID21859710.
  8. ^Isidro, F. (2014)."Cannabinoids for treatment of Alzheimer's disease: moving toward the clinic".Frontiers in Pharmacology.5:37.doi:10.3389/fphar.2014.00037.PMC3942876.PMID24634659.
  9. ^Christie, W.W. (April 16, 2012)."Phosphatidylethanolamine and Related Lipids".The AOCS Lipid Library. Archived fromthe originalon August 21, 2012.RetrievedSeptember 3,2012.
  10. ^Gbaguidi, B.; Hakizimana, P.; Vandenbussche, G.; Ruysschaert, J.-M. (2007)."Conformational changes in a bacterial multidrug transporter are phosphatidylethanolamine-dependent"(PDF).Cellular and Molecular Life Sciences.64(12): 1571–82.doi:10.1007/s00018-007-7031-0.PMID17530171.S2CID2078590.
  11. ^Kelly, Karen (July 28, 2011)."Phospholipid Biosynthesis".The AOCS Lipid Library.RetrievedSeptember 3,2012.
  12. ^Kuge, Osamu; Nishijima, Masahiro (1 April 2003)."Biosynthetic Regulation and Intracellular Transport of phosphatidylserine in Mammalian Cells".The Journal of Biochemistry.133(4): 397–403.doi:10.1093/jb/mvg052.PMID12761285.Archived fromthe originalon 30 January 2021.Retrieved30 January2021.
  13. ^abOak, Jeong-Ho; Nakagawa, Kiyotaka; Miyazawa, Teruo (2002)."UV analysis of Amadori-glycated phosphatidylethanolamine in foods and biological samples".The Journal of Lipid Research.43(3): 523–9.doi:10.1016/S0022-2275(20)30158-9.PMID11893788.
  14. ^Oak, Jeong-Ho; Nakagawa, Kiyotaka; Miyazawa, Teruo (2000)."Synthetically prepared Amadori-glycated phosphatidylethanolamine can trigger lipid peroxidation via free radical reactions".FEBS Letters.481(1): 26–30.Bibcode:2000FEBSL.481...26O.doi:10.1016/S0014-5793(00)01966-9.PMID10984609.S2CID23265125.
  15. ^Oak, Jeong-Ho; Nakagawa, Kiyotaka; Oikawa, Shinichi; Miyazawa, Teruo (2003). "Amadori-glycated phosphatidylethanolamine induces angiogenic differentiations in cultured human umbilical vein endothelial cells".FEBS Letters.555(2): 419–23.Bibcode:2003FEBSL.555..419O.doi:10.1016/S0014-5793(03)01237-7.PMID14644453.S2CID33974755.
  16. ^Eitsuka, Takahiro; Nakagawa, Kiyotaka; Ono, Yuichi; Tatewaki, Naoto; Nishida, Hiroshi; Kurata, Tadao; Shoji, Naoki; Miyazawa, Teruo (2012)."Amadori-glycated phosphatidylethanolamine up-regulates telomerase activity in PANC-1 human pancreatic carcinoma cells".FEBS Letters.586(16): 2542–7.Bibcode:2012FEBSL.586.2542E.doi:10.1016/j.febslet.2012.06.027.PMID22750441.S2CID5452160.
  17. ^Ariizumi, Ken; Koike, T; Ohara, S; Inomata, Y; Abe, Y; Iijima, K; Imatani, A; Oka, T; Shimosegawa, T (2008)."Incidence of reflux esophagitis and H pylori infection in diabetic patients".World Journal of Gastroenterology.14(20): 3212–7.doi:10.3748/wjg.14.3212.PMC2712855.PMID18506928.

External links[edit]

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