The analysis of fluorophore-labeled glycans by high-resolution polyacrylamide gel electrophoresis

Many important biological processes are mediated by the carbohydrate moieties of glycoconjugates. Their structural determination presents considerable difficulties because of both their complex structures and the small quantities which are available from biological sources. In order to address some of the problems in this field a new method of glycan analysis has been developed in which saccharides having a reducing end group are labeled covalently with a fluorophore and the derivatives separated with high resolution by polyacrylamide gel electrophoresis. Fluorophores have been used that enable the electrophoretic separation of positional isomers, anomers, and epimers of a variety of saccharides. Mixtures of complex glycans obtained by enzymatic cleavage from glycoproteins yield electrofluorograms showing high-resolution oligosaccharide profiles. Techniques for obtaining saccharide sequence information from isolated oligosaccharides have been developed. Subpicomolar quantities of individual saccharides can be detected using an imaging system based on a cooled charge-coupled device. The method enables rapid, simultaneous, parallel analyses of multiple samples. The analytical and clinical applications and potential of the system are discussed.