High resolution and rapid analysis of branched oligosaccharides by capillary electrophoresis

The fluorophore 2-aminoacridone has been used to label a number of branched oligosaccharides previously released from various glycoproteins. Complex glycans were derivatized via their reducing end with this fluorophore by a Schiff's base mechanism followed by reduction to a secondary amine using sodium cyanoborohydride. This process of derivatization was carried out efficiently and in a nonselective manner over a period of 30 min at 90 degrees C. The resulting derivatives were separated with high resolution by capillary electrophoresis using borate buffer, containing taurodeoxycholate, as the separation buffer. The method described does not require the removal of sialic acid residues prior to derivatization, so that treatment of glycans with N-acetyl neuraminidase provided useful and additional structural information. Attempts have also been made to relate the electrophoretic mobility of branched oligosaccharides with their molecular volume.