Affinity chromatography is a very powerful technique that exploits the binding affinities of target molecules (typically proteins) for substances covalently linked to beads. For example, if one wanted to separate all of the proteins in a sample that bound to ATP from proteins that do not bind ATP, one could covalently link ATP to support beads and then pass the sample through column. All proteins that bind ATP will “stick" to the column, whereas those that do not bind ATP will pass quickly through it. The proteins adhering to the column may then released from the column by adding ATP.
Figure 9.5.1: Affinity Chromatography