Ether lipid

Ether lipid

Ether lipids are lipids in which one or more of the carbon atoms on glycerol is bonded to an alkyl chain via an ether linkage, as opposed to the usual ester linkage.

Types

Ether lipids are called plasmalogens (1-O-1'-alkenyl-2-acylglycerophospholipids) if these are glycerol-containing phospholipids with an unsaturated "O"-(1-alkenyl) (vinyl ether) group at the first position on the glycerol chain.

Platelet-activating factor is an ether lipid which has an acetyl group instead of an acyl chain at the second position (SN-2).

Biosynthesis

The formation of the ether bond in mammals requires two enzymes, dihydoxyacetonephosphate acyltransferase (DHAPAT) and alkyldihydroxyacetonephosphate synthase (ADAPS), that reside in the peroxisome. cite journal |author=Hajra AK |title=Glycerolipid biosynthesis in peroxisomes (microbodies) |journal=Prog. Lipid Res. |volume=34 |issue=4 |pages=343–64 |year=1995 |pmid=8685243 |doi=] Accordingly, peroxisomal defects often lead to impairment of ether-lipid production.

Functions

tructural

Plasmalogens as well as some 1-O-alkyl lipids are ubiquitous and sometimes major parts of the cell membranes in mammals and anaerobic bacteria. [cite journal |author=Paltauf F |title=Ether lipids in biomembranes |journal=Chem Phys Lipids |volume=74 |issue=2 |pages=101–39 |year=1994 |pmid=7859340 |doi=10.1016/0009-3084(94)90054-X] In archaea, ether lipids are the major polar lipids in the cell envelope and their abundance is one of the major characteristics that separate this group of prokaryotes from the bacteria. In these cells, diphytanylglycerolipids or bipolar macrocyclic tetraethers can form covalently linked 'bilayers'. [cite journal |author=Koga Y, Morii H |title=Recent advances in structural research on ether lipids from archaea including comparative and physiological aspects |url=http://www.jstage.jst.go.jp/article/bbb/69/11/69_2019/_article |journal=Biosci Biotechnol Biochem |volume=69 |issue=11 |pages=2019–34 |year=2005 |pmid=16306681 |doi=10.1271/bbb.69.2019]

econd messenger

Differences between the catabolism of ether glycerophospholipids by specific phospholipases enzymes might be involved in the generation of lipid second messenger systems such as prostaglandins and arachidonic acid that are important in signal transduction. [cite journal |author=Spector A, Yorek M |title=Membrane lipid composition and cellular function |url=http://www.jlr.org/cgi/reprint/26/9/1015 |journal=J Lipid Res |volume=26 |issue=9 |pages=1015–35 |year=1985 |pmid=3906008] Ether lipids can also act directly in cell signaling, as the platelet-activating factor is an ether lipid signaling molecule that is involved in leukocyte function in the mammalian immune system. [cite journal |author=Demopoulos C, Pinckard R, Hanahan D |title=Platelet-activating factor. Evidence for 1-O-alkyl-2-acetyl-sn-glyceryl-3-phosphorylcholine as the active component (a new class of lipid chemical mediators) |url=http://www.jbc.org/cgi/reprint/254/19/9355 |journal=J Biol Chem |volume=254 |issue=19 |pages=9355–8 |year=1979 |pmid=489536]

Antioxidant

Another possible function of the plasmalogen ether lipids is as antioxidants, as protective effects against oxidative stress have been demonstrated in cell culture and these lipids might therefore play a role in serum lipoprotein metabolism. [cite journal |author=Brosche T, Platt D |title=The biological significance of plasmalogens in defense against oxidative damage |journal=Exp Gerontol |volume=33 |issue=5 |pages=363–9 |year=1998 |pmid=9762517 |doi=10.1016/S0531-5565(98)00014-X] This antioxidant activity comes from the enol ether double bond being targeted by a variety of reactive oxygen species. [cite journal |author=Engelmann B |title=Plasmalogens: targets for oxidants and major lipophilic antioxidants |journal=Biochem Soc Trans |volume=32 |issue=Pt 1 |pages=147–50 |year=2004 |pmid=14748736 |doi=10.1042/BST0320147]

ynthetic ether lipid analogs

Synthetic ether lipid analogs have cytostatic and cytotoxic properties, probably by disrupting membrane structure and acting as inhibitors of enzymes within signal transmission pathways, such as protein kinase C and phospholipase C.

A toxic ether lipid analogue miltefosine has recently been introduced as an oral treatment for the tropical disease leishmaniasis, which is caused by leishmania, a protozoal parasite with a particularly high ether lipid content in its membranes. [cite journal |author=Lux H, Heise N, Klenner T, Hart D, Opperdoes F |title=Ether--lipid (alkyl-phospholipid) metabolism and the mechanism of action of ether--lipid analogues in Leishmania |journal=Mol Biochem Parasitol |volume=111 |issue=1 |pages=1–14 |year=2000 |pmid=11087912 |doi=10.1016/S0166-6851(00)00278-4]

References

External links

*


Wikimedia Foundation. 2010.

Look at other dictionaries:

  • Lipid signaling — Lipid signaling, broadly defined, refers to any biological signaling event involving a lipid messenger that binds and activates a receptor. Lipid signaling is thought to be qualitatively different from other classical signaling paradigms (such as …   Wikipedia

  • lipid — lip id n. [Gr. li pos fat.] (Chem., Biochem.) Any of a variety of oily or greasy organic compounds found as major structural components of living cells; they are insoluble in water but soluble in organic solvents such as alcohol and ether, and… …   The Collaborative International Dictionary of English

  • lipid — /lip id, luy pid/, n. Biochem. any of a group of organic compounds that are greasy to the touch, insoluble in water, and soluble in alcohol and ether: lipids comprise the fats and other esters with analogous properties and constitute, with… …   Universalium

  • Lipid — Structures of some common lipids. At the top are oleic acid[1] and cholesterol.[2] The middle structure is a triglyceride composed of oleoyl, stearoyl, and palmitoyl chains at …   Wikipedia

  • Lipid — Another word for fat. (Please see the various meanings of Fat.) A lipid is more formally defined as a substance such as a fat, oil or wax that dissolves in alcohol but not in water. Lipids contain carbon, hydrogen and oxygen but have far less… …   Medical dictionary

  • lipid — also lipide noun Etymology: International Scientific Vocabulary Date: 1912 any of various substances that are soluble in nonpolar organic solvents (as chloroform and ether), that are usually insoluble in water, that with proteins and… …   New Collegiate Dictionary

  • NCEH1 — Neutral cholesterol ester hydrolase 1 Identifiers Symbols NCEH1; AADACL1; KIAA1363; NCEH External IDs …   Wikipedia

  • Plasmalogene — Ein typisches Plasmalogen Plasmalogene sind Etherlipide, die strukturell den Phosphatidylcholinen bzw. Phosphatidylethanolaminen ähneln. Unterschied ist jedoch ein am endständigen Kohlenstoff Atom des Glycerins anstelle eines Fettsäure Esters als …   Deutsch Wikipedia

  • Plasmalogen — A plasmalogen is an ether lipid where the first position of glycerol binds a vinyl residue (from a vinyl alcohol) with the double bond next to the ether bond. The second carbon has a typical ester linked fatty acid, and the third carbon usually… …   Wikipedia

  • Alkenylglycerophosphocholine hydrolase — In enzymology, an alkenylglycerophosphocholine hydrolase (EC number|3.3.2.2) is an enzyme that catalyzes the chemical reaction:1 (1 alkenyl) sn glycero 3 phosphocholine + H2O ightleftharpoons an aldehyde + sn glycero 3 phosphocholineThus, the two …   Wikipedia

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”