Determination of the number and distribution of oligosaccharide linkage positions in O-linked glycoproteins by capillary electrophoresis.

O-Linked oligosaccharide chains are found in a wide variety of glycoproteins. Determination of the number of O-linked serine and threonine residues is an important step in glycoprotein characterization. Alkaline release of the oligosaccharide chains from the peptide chain followed by bisulfite addition to the unsaturated residues generates sulfonates. Hydrolysis of treated samples followed by derivatization with naphthalene 2,3-dicarboxyaldehyde and cyanide results in analytes which are separated and quantitated by capillary electrophoresis with UV detection. The utility of the method was demonstrated using bovine submaxillary mucin yielding results that agreed with previously published values.