Binding of concanavalin A to calf brain synaptic vesicles.

Concanavalin A was employed as a tool to investigate the organization of synaptic vesicle glycoproteins. The lectin was incubated in the presence of both intact and Triton X-100 treated calf brain synaptic vesicles. Electrophoresis of treated membranes clearly demonstrated that the majority of Concanavalin A binding sites was not exposed in intact synaptic vesicles. The vesicles were isolated by the procedure of DeLorenzo and Freedman (DeLorenzo, R. J., and Freedman, S. D. (1978) Biochem. Biophys. Res. Commun. 80, 183-192). However, an extra centrifugation step at 55,000 g was required to obtain plain vesicles nearly free from coated vesicles and membrane fragments.