Sphingosines moiety

Figure 12.6. Structures of Sphingosine and Sphingomyelin. The sphingosine moiety of sphingomyelin is highlighted in blue.

From the point of view of solubility characteristics, the fatty acid group and the sugar moiety in the sphingosine moiety have opposing effects. Thus, the long-chain fatty acids are extremely soluble in solvents for fats, and have a strongly hydrophobic character. 

The linkage between the sphingosine moiety and the D-galactose residue was determined by Carter and Greenwood.83 Catalytic reduc-... 

The anomeric configuration of the D-galactopyranosyl group on the sphingosine moiety was determined by the degradation method of... 

According to Klenk, the fatty acids bound covalently to the amino group of the sphingosine moiety consist mainly of stearic acid the sugars are D-galactose (as in the cerebrosides) and D-glucose. 

In GD, as in normals, the double bond of the sphingosine moiety is located between C-4 and C-5 in trans-configuration. 

Numerous chemical analyses in NPD have failed to produce evidence of an abnormal sphingomyelin molecule. As in the normal sphingosine moiety there is a double bond between carbon atoms 4 and 5. The amino group (Cg) and hydroxyl group (C3) are in the erythro-configuration. 

Glycolipids.—2-G-Acyl-l-0-alkyl-3-C>-(j8-D-galactopyranosyl 3-sulphate)-gIycerol has been labelled with [ S]sulphate the labelled glycolipid was used as the substrate in studies of the specificities of human arylsulphatases A and B. Oxidative ozonolysis of the alkenic bond of the sphingosine moiety of either globoside (47) or the methyl ester of haematoside (48) allowed the product to be... 

FIGURE 3.10 Biosynthetic pathway of ceramide. SPT, serine palmitoyltransferase 3-KSR, 3-ketosphinganine reductase Cer-Synthase, ceramide synthase. In fact, the reaction catalyzed by ceramide synthase leads to dihydroceramide. Ceramide is obtained by the secondary action of a desaturase that creates a trans double bond between carbons C4 and C5 of the sphingosine moiety (A). 

Last, but not least, the presence of double bonds in the final product precludes the classical use of hydrogenation conditions, subsequent to the introduction of the unsaturated chain. This means for example that the very classical benzyl ether cannot be used as a protecting group in the last steps. This kind of problem is similar to the one met in the synthesis of sphingoglycolipids where a double bound is also present in the sphingosine moiety. 

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