Colchicine binding to antibodies.

Abstract

Antibodies to colchicine have been prepared by injecting rabbits with an antigen prepared by coupling deacetylcolchicine to bovine serum albumin with a water-soluble carbodiimide. Sera of high titer were obtained with apparent dissociation constants for colchicine ranging from 5 to 17 nM. Binding was rapid and occurred at low temperatures. The chemical specificity of the binding site(s) resembled that in tubulin for the A and B rings of colchicine. Unlike tubulin, the antibody binding site tolerated numerous changes in the tropolone moiety (C ring). In contrast to tubulin, binding of colchicine to the antibody site did not promote fluorescence. The colchicine binding capacity of the antibody was high enough to prevent colchicine fluorescence in the presence of tubulin and to restore polymerization in colchicine-inhibited tubulin preparations.