Affinity Ultrafiltration of Proteins

Abstract

Affinity ultrafiltration combines high-volume processing capability of membrane filtration with high selectivity, which can be achieved in affinity methods of protein purification. This technique is based on the principle that when a protein to be purified is free in solution, it passes through the ultrafiltration membrane, whereas when it is bound to a macromolecular affinity ligand placed on one side of the membrane, it is constrained to that side of the membrane. Compounds which do not bind to the ligand pass freely through the membrane and are thus separated from the protein-ligand complex. After all the undesired components have been removed, the protein is desorbed from the ligand by addition of an appropriate dissociating medium and then recovered in the filtrate. The review describes basic principles and characteristics of the method. In addition, some applications of affinity ultrafiltration for protein purification are given.