Analysis of glycoprotein oligosaccharides by fast atom bombardment mass spectrometry

A strategy is outlined for isolation and structural analysis of oligosaccharides derived from glycoproteins. Oligosaccharides, N- and O-linked, are released by chemical and enzymatic methods and separated using gel filtration, concanavalin A affinity chromatography and high-performance ion-exchange chromatography. Structural studies are carried out by fast atom bombardment mass spectrometry. The structural information from the latter can be extended to include determination of binding positions between monosaccharide residues. Prior to the analysis, samples are subjected to periodate oxidation, reduction and permethylation. The positions of glycosidic linkages are deduced from the spectrum by the primary and secondary sequence ions. Structural information can be obtained from mixtures of isomeric compounds.