Measurement of Protein−Ligand Binding Constants from Reaction-Diffusion Concentration Profiles

Protein−ligand dissociation constants, K d, are determined precisely and down to the picomolar range from reaction-diffusion (RD) concentration profiles created by proteins diffusing through hydrogels functionalized with protein ligands. The RD process effectively amplifies the molecular-scale binding events into macroscopic patterns visible to the naked eye. The method is applicable to various protein−ligand pairs and does not require any prior knowledge about the protein structure.