Chapter 17 Lipids 17.6 Sphingolipids

Sphingosine Sphingosine is an 18-carbon unsaturated amino alcohol.

Ceramides In a ceramide, the NH2 group in sphingosine is attached by an amide bond to a fatty acid

Sphingolipids Sphingolipids are similar to glycerophospholipids contain sphingosine, a fatty acid, phosphate, and an amino alcohol

Sphingomyelin Sphingomyelin is a sphingolipid found in nerve cells bonds the —OH of a ceramide to a phosphate ester of choline

Glycosphingolipids Glycosphingolipids are sphingolipids that contain monosaccharides attached by a -glycosidic bond to the —OH group of ceramide

Cerebrosides Cerebrosides contain galactose or glucose attached by a -glycosidic bond to the —OH group of ceramide are found in the brain and the myelin sheath are important in cellular recognition and tissue immunity

Gangliosides Gangliosides are sphingolipids that contain chains of two to seven monosaccharides are important in neurons are found on cell membrane surfaces act as receptors for hormones, viruses, and drugs can cause genetic diseases if they accumulate

Gangliosides (continued) GM2 is a ganglioside that accumulates in Tay-Sachs disease when hexoamidase A is defective

Lipid Diseases (Lipidoses) In many lipid diseases, the deficiency of an enzyme causes the accumulation of glycolipids

Learning Check Identify each as a 1) fatty acid 2) triacylglycerol 3) amino alcohol 4) glycerophospholipid 5) glycosphingolipid A. Glyceryl trioleate B. Cephalin C. Choline D. Galactocerebroside E. Palmitic acid

Solution Identify each as a 1) fatty acid 2) triacylglycerol 3) amino alcohol 4) glycerophospholipid 5) glycosphingolipid A. Glyceryl trioleate 2) triacylglycerol B. Cephalin 4) glycerophospholipid C. Choline 3) amino alcohol D. Galactocerebroside 5) glycosphingolipid E. Palmitic acid 1) fatty acid