Affinity chromatography is a chromatography method separating biomolecules based on the specific interaction among biomolecules. Examples of such binding can be found in the binding between enzyme and substrate, receptor and ligand as well as antibody and antigen. This type of binding is both specific and reversible, which enables the purification of protein via reversible binding and separation. Affinity chromatography enjoys excellent selectivity, allowing rapid target protein capture from protein complexes with purity higher than 90% via one-step purification.