Purification of brain tubulin by affinity chromatography on immobilized lactoperoxidase

Brain tubulin binds to lactoperoxidase coupled to Affigel 10 through a 10 A succinylated aminoalkyl spacer and can be eluted by an ionic strength gradient. The tubulin can be obtained about 90% electrophoretically pure in 2 to 3 h without glycerol or GTP. It retains its ability to bind colchicine. Compared to tubulin purified by the assembly-disassembly procedure, affinity-purified tubulin has a higher critical concentration for polymerization and the purified protein appears to be free of high molecular weight microtubule-associated proteins. Tubulin binding to the lactoperoxidase affinity column protects the colchicine binding site against decay at 4 degrees C, whereas the interaction of tubulin with soluble lactoperoxidase does not.