Glycoproteins from adult rat brain synaptic vesicles. Fractionation on four immobilized lectins

Glycoproteins obtained from large amounts of highly purified synaptic vesicles isolated from adult rat brain were fractionated by sequential affinity chromatography in the presence of SDS on four different immobilized lectins: concanavalin A, Ulex europeus lectin, Ricinus sanguinis lectin and wheat germ agglutinin. 83% of the total protein-bound sugar of synaptic vesicles can be adsorbed on the lectins and separated from the bulk of carbohydrate free proteins. Nine fractions containing only glycoproteins and differing by their terminal sugars were separated by analysed for their carbohydrate composition and electrophoretic profiles. A considerable heterogeneity of the glycoprotein population was observed which cannot be explained solely by the microheterogeneity of the glycans of the synaptic vesicle glycoproteins.