Lipids composed of one molecule of long-chain fatty acid, one molecule of sphingosine or its derivatives and one molecule of polar alcohol
Sphingolipids refer to lipids composed of a molecule of long-chain fatty acid, a molecule of sphingosine or its derivatives and a molecule of polar alcohol.Sphingosine is the parent compound of many long-chain amino alcohols in sphingolipids, which is abundant in mammals.The polar head group of sphingolipids binds to the hydroxyl group of sphingosine, while the fatty acid part forms an amide bond with its amino group.
Sphingolipids have one polar head group and two nonpolar tails (long hydrocarbon chains of fatty acids and sphingosine), which belong to polaritylipid, is second only tophospholipidThe second major type of membrane lipids.
classification
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Sphingolipids can be divided into sphingomyelin, glycosphingolipids andGanglioside3 subclasses.
Sphingomyelin
Sphingolipids are the simplest and most abundant sphingolipids in animal tissues. Their polar heads are phosphatidylcholine or phosphatidylethanolamine.Because it contains phosphorus, it can also be classified as phospholipids.General properties of sphingomyelinPhosphatidylcholineandPhosphatidylethanolamineSimilar, with the same charge as them.Animal cellSphingolipids are present in most membranes of.The myelin sheath around some nerve cells is very rich in sphingomyelin.
Glycosphingolipid
Cerebroside does not contain phosphorus, nor is it charged, because its polar head group is neutral.It is characterized by containing one or more sugar units, so it is also often called glycosphingolipid.MembranousGalactocerebrosideThe polar head group of is galactose;The polar head of glucocerebroside in non nerve tissue membrane is glucose.There are also some more complex cerebrosides containing 2, 3 or 4 sugar groups, which exist in the outer layer of cell membrane and are composed ofcell surfaceImportant components of.The sugar can beD-glucose、D-galactoseOr N-acetyl-D-galactosamine.
Ganglioside
Gangliosides are the most complex glycosphingolipids, which contain giant polar heads composed of several glycosyl groups.Such compounds are characterized by that one or more terminal sugar groups in the molecule areN-acetylneuraminic acid(Sialic acid), which is negatively charged at pH7.Sialic acid also exists in the oligosaccharide side chains of some membrane glycoproteins.Gangliosides account for about 6% of the membrane lipids of the brain gray matter, and less in most non nerve tissues.Gangliosides are important components of specific receptor sites on the surface of cell membrane, and are associated with blood group specificity, tissue immunity andCell recognitionIt may have something to do with it.
