Linkage Structure of Carbohydrates by Gas Chromatography-Mass Spectrometry (GC-MS) of Partially Methylated Alditol Acetates

Enormous potential for chemical and structural diversity is provided by the variety of ways each sugar can be linked, so it is not surprising that oligosaccharide moieties of glycoproteins and glycolipids participate in more subtle roles in cell recognition, surface sensing, and, perhaps, an even wider range of functions of unrealized dimension. A fun damental step in understanding the three-dimensional structure of the carbohydrate is to determine how the sugar components are linked; the most widely used method for determining linkage structure of polysaccharides is methylation analysis by gas chromatography (GC) of partially methylated alditol acetate derivatives of neutral and amino sugars. Glycolipids require little additional preparation, but with glycoproteins, the cleavage of the carbohydrate moieties from the peptides may be necessary for several reasons. Material can be purified from the methylation reaction mixtures in several ways.