Purification and Chemical Properties of Brain Tubulin

This chapter presents the modified procedure involved in purifying brain tubulin developed originally by Weisenberg and presents the current information on the structure of tubulin. Microtubules are found in a wide variety of animal and plant cells. In dividing cells they are localized in the mitotic apparatus and are also found in axonal and dendritic processions of neurons. They have been implicated in a number of different cellular functions. Structurally, microtubules are composed of protofilaments of the subunit protein, tubulin. Because of the wide distribution of this organelle and the large number of different cellular processes in which it seems to participate, microtubule has been the target of intensive investigation. The purification procedure enables obtaining tubulin greater than 95% homogeneous. By employing highly purified samples, it is much easier to establish a meaningful structure–function relationship with minimal complication from other components. Employing such protein helps establish the minimum conditions in which the protein can undergo in vitro reconstitution and ligand-induced polymerization.