Separation of Asn-linked sialyloligosaccharides labeled with p-aminobenzoic acid ethyl ester by high-performance liquid chromatography.

Sialylated Asn-linked oligosaccharide units that are present in glycoproteins are often extensively heterogeneous in number, in the linkage type and location of the sialic acid (NeuAc) residues, and in the underlying asialo core oligosaccharides. Their structural characterization requires the complex mixture of oligosaccharides to be separated and purified to homogeneity. Baenziger and coworkers1~4) have introduced some rapid and sensitive methods which involve reducing the oligosaccharides with NaB3H4 and subsequently fractionating the mixture by HPLC. Recently, Yamamoto et a/.5 6) have developed a fluorescent HPLCprocedure for a sensitive detection and fractionation of anionic oligosaccharides. As an alternative to radioactive and fluorescent HPLC,procedures for labeling oligosaccharides with the ultra-violet absorbing reagent, /?-aminobenzoic acid ethyl ester (ABEE), have