Polyacrylamide gel electrophoresis of reducing saccharides labeled with the fluorophore 8-aminonaphthalene-1,3,6-trisulphonic acid: application to the enzymological structural analysis of oligosaccharides

Mono- and oligosaccharides, each containing a reducing end group, were labeled with the charged fluorophore 8-aminonaphthalene-1,3,6-trisulphonic acid and the resulting derivatives were separated with high resolution by polyacrylamide gel electrophoresis using a method developed recently (P. Jackson, Biochem. J. 1990, 270, 705-713) but with an alternative electrophoretic buffer system. The fluorescent derivatives of glucose and all its straight chain, alpha 1-4 linked, oligomers from maltose to maltoheptaose were well resolved. Various isomers such as maltose and lactose could be separated, as were maltose and cellobiose and some epimers, for instance glucose and galactose. The method was applied to the analysis of the partial sequential degradation of a complex oligosaccharide with neuraminidase and beta-galactosidase. Gels showing fluorescent saccharide band patterns were recorded in picomolar quantities either photographically or using an imaging system based on a cooled charge-coupled device.