Measuring binding constants of His-tagged proteins using affinity chromatography and Ni-NTA-immobilized enzymes.

Affinity chromatography is one way to measure the binding constants of a protein-ligand interaction. Here we describe a method of measuring a binding constant using Ni-NTA resin to immobilize a His-tagged enzyme and the method of frontal analysis. While other methods of immobilization are possible, using the strong affinity interaction between His-tagged proteins and Ni-NTA supports results in a fast, easy, and gentle method of immobilization. Once the affinity support is created, frontal analysis can be used to measure the binding constant between the protein and various analytes.