Crystallization And Purification Of Polypeptides

Abstract

The invention is directed to a method of highly purifying a polypeptide or other biological compounds from a contaminant by crystallization comprising contacting a mixture containing uncrystallized polypeptides and a contaminant with an exogenous nucleating agent, crystallizing the polypeptides, thereby forming at least one crystal of the polypeptide attached to the nucleating agent, the attached crystal being of a high purity, and at least one polypeptide crystal unattached to the nucleating agent, the unattached crystal being of a lower purity than the attached crystal, and separating the crystal attached to the nucleating agent from the crystal unattached to the nucleating agent. Also, the invention is directed to a method of purifying a polypeptide in a high purity and in a high yield from a contaminant by crystallization comprising contacting a mixture containing uncrystallized polypeptides and a contaminant with an exogenous nucleating agent that has a close lattice match to the polypeptide, crystallizing the polypeptides, thereby forming at least one crystal of the polypeptide attached to the nucleating agent, the attached crystal being of a high purity and produced in a high yield, and at least one crystal unattached to the nucleating agent, the unattached crystal being of a lower purity than the attached crystal, and separating the crystal attached to the nucleating agent from the crystal unattached to the nucleating agent. The invention is also directed to compositions comprising highly purified polypeptide or biological compound crystals and compositions of highly purified polypeptides or biological compounds.