13] Inositol-containing sphingolipids

Abstract

Publisher Summary Glycophosphosphingolipids (GPSs) are membrane glycolipids containing a phosphodiester linkage between inositol and ceramide. The structure, “inositol (1-O)-phosphoryl-(O-1)ceramide” constitutes a common core. This chapter discusses some known glycophosphophingolipids. There is also a discussion of the procedure of isolation of a glycophosphosphingolipid fraction from plants. There is a description of the production of a carboxyl-reduced oligosaccharide mixture from the glycophosphoceramide concentrate. To isolate major fractions of the oligosaccharides, gel permeation chromatography on Bio-Rad P gels is used, effectively separating oligo saccharide fractions up to 10 sugars in length. Several methods in high-performance liquid chromatography (HPLC) can be utilized for further purification of the oligosaccharides, including reversed-phase separation of the acetylated derivatives and amino-derivatized normal-phase chromatography on silica gel. Detection methods include (1) benzoylation of the amino group on the glucosamine, (2) use of fluorescamine or o-phthaldehyde to synthesize a fluorophore on the glucosamine in glucosamine-containing GPSs for fluorescence detection of the molecules, and (3) use of tritiated acetic anhydride for radiolabeling of the aminosugar. High-performance thin-layer chromatography can complement these methods. There is also some discussion in the chapter about the new methods of sequence determination using fast atom bombardment mass spectrometry.