21.1 Affinity Chromatography:
Affinity chromatography is a powerful technique used to purify enzymes by taking advantage of their specific binding properties to certain molecules, called ligands, which are attached to a stationary phase. The enzyme is passed through a chromatography column containing the ligand, and if the enzyme has affinity towards it, it will bind specifically to the column, while other impurities will flow through. After washing the column with buffer solution, the enzyme is eluted out by changing the conditions of the buffer, such as pH or salt concentration, resulting in a highly purified enzyme sample.