Synthesis and characterization of soluble concanavalin A oligomer

Concanavalin A, (Con A, MW 26,500/monomer unit) was crosslinked with glutaraldehyde to form soluble, high‐molecular‐weight (larger than MW 300,000) Con A Oligomers. After filtration to remove insoluble and low‐molecular‐weight portions (below 300,000 daltons), the size and molecular‐weight distribution were characterized by laser light scattering and gel‐filtration chromatography. The molecular‐size determined by laser light scattering ranged from 870 to 4070 Å, while the molecular weight determined by gel chromatography ranged from 6 × 10 5 to higher than 2 × 10 6 daltons. The affinity and kinetics of Con A oligomer binding to polysaccharide (glycogen) were evaluated by precipitation test and turbidity development, respectively. The binding with glycogen was strongest at neutral pH and showed similar activity to unmodified Con A molecules. The binding constants of α‐ D ‐glucose and succinyl‐aminophenyl α‐ D glucopyranoside‐insulin to Con A oligomer were 1.0 × 10 3 M −1 and 4.5 × 10 4 M −1 , respectively and the binding capacity of the oligomer was nearly 85% to 95% of monomeric Con A. The complexes of saccharides and soluble Con A oligomer were stable for at least 7 days. © 1993 Wiley & Sons, Inc.