Immobilized metal ion affinity chromatography (IMAC) exploits a molecule’s affinity for chelated metal ions. The amino acid histidine present in many proteins forms complexes with transition metal ions such as Cu2+, Zn2+, Ni2+ and Fe3+. Chelating Sepharose™ Fast Flow with a suitable immobilized metal ion will therefore selectively retain proteins with exposed histidine.
