Phosphatidylethanolamine

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Phosphatidylethanolamine
Identifiers
PubChem446872
ChemSpider394115 YesY
MeSHphosphatidylethanolamines
Jmol-3D imagesImage 1
 YesY (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references
 
  (Redirected from Cephalin)
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Phosphatidylethanolamine
Identifiers
PubChem446872
ChemSpider394115 YesY
MeSHphosphatidylethanolamines
Jmol-3D imagesImage 1
 YesY (verify) (what is: YesY/N?)
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Phosphatidylethanolamine (cephalin, sometimes abbreviated PE) is a lipid found in biological membranes. It is synthesized by the addition of CDP-ethanolamine to diglyceride, releasing CMP. S-adenosyl methionine can subsequently methylate the amine of phosphatidyl ethanolamine to yield phosphatidyl choline.

Cephalin is a phospholipid, which is a lipid derivative. It is not to be confused with the molecule of the same name that is an alkaloid constituent of Ipecac.

Contents

Function

Cephalin is found in all living cells, although in human physiology it is found particularly in nervous tissue such as the white matter of brain, nerves, neural tissue, and in spinal cord. Whereas phosphatidylcholine is the principal phospholipid in animals, cephalin is the principal one in bacteria.

As a polar head group, phosphatidylethanolamine (PE) creates a more viscous lipid membrane compared to phosphatidylcholine (PC). For example, the melting temperature of di-oleoyl-PE is -16C while the melting temperature of di-oleoyl-PC is -20C. If the lipids had two palmitoyl chains, PE would melt at 63C while PC would melt already at 41C (See references in Wan et al. Biochemistry 47 2008). Lower melting temperatures correspond, in a simplistic view, to more fluid membranes.

One of the primary roles for PE in bacterial membranes is to spread out the negative charge caused by anionic membrane phospholipids. In the bacterium E. coli, PE play a role in supporting lactose permease's active transport of lactose into the cell, and may play a role in other transport systems as well. PE 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 their tertiary structures so that they can function properly. When PE is not present, the transport proteins have incorrect tertiary structures and do not function correctly. [1]

Chemistry

Biosynthesis of Phophatidylethanolamine in Bacteria

In the chemical sense, cephalin is phosphatidylethanolamine. As a lecithin, it consists of a combination of glycerol esterified with two fatty acids and phosphoric acid. Whereas the phosphate group is combined with choline in phosphatidylcholine, it is combined with the ethanolamine in Cephalin.

The two fatty acids may be the same, or different, and are usually in the 1,2 positions (though can be in the 1,3 positions).

See also

External links

Additional images

References

  1. ^ Christie, W.W. (April 16, 2012). "Phosphatidylethanolamine and Related Lipids". The AOCS Lipid Library. http://lipidlibrary.aocs.org/lipids/pe/index.htm. Retrieved September 03, 2012.