Phosphosphingolipids sphingolipids

Figure 1.6. Typical structures of sphingolipids (phosphosphingolipid and glycosphingolipid classes), based on a dl8 l ceramide (R = fatty acid group).

The primary hydroxyl group is substituted in one of two ways to give two classes of sphingolipid these are the phosphosphingolipids and glycosphingolipids. 

SM is the major phosphosphingolipid in mammalian tissues and lipoproteins, and has been studied extensively with respect to its role in the formation of sterol-enriched ordered membrane domains and cell signaling (J. Slotte, 2006). Like Cers (and most other complex sphingolipids), SMs typically have high phase-transition temperatures (>37°C), which is a factor in their tendency to associate with rafts. 

D- Aro-Sphingosine (961) is an important component of all sphingolipids of the glyco-sphingolipid and phosphosphingolipid types. Glycosphingosines, as well as sphingosine... 

Thus, the ions of m/z 421 and 720 in the negative ion mode are found to be very useful for the structural determination of glycosyl phosphosphingolipids (phosphodihexose-sphingolipids) in the analyses by FAB mass spectrometry, because these ion peaks are characteristic of a phosphodihexose and a phytosphingosine (4-hydroxy-Ci -sphinganine) containing phosphodihexose, respectively. 

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