Deacetylcolchicine conjugated to a heme-nonapeptide act with both soluble tubulin and microtubules polymerized in vitro.

A heme-nonapeptide with peroxidase-like activity was conjugated to pure deacetylcolchicine. This conjugated colchicine derivative competitively inhibits colchicine binding to soluble tubulin and is also able to depolymerize microtubules in vitro. Cytochemical studies show that at substoichiometric concentrations of the derivative, microtubules from the same sample are decorated to varying extents. These findings indicate that the binding of the colchicine-derivative to microtubules causes them to depolymerize.