A system and method for determining the dissociation constant for a particular ligand is disclosed. In accordance with certain embodiments, the method creates a chemical denaturation curve of a protein in the absence of the ligand. A particular point is selected from this curve, such as the point at which 90% of the protein is unfolded. The molarity of chemical denaturant is determined for this selected point. A one point test is then performed for the protein with a predetermined concentration of the particular ligand. The fraction of protein which is unfolded at this point is then used to determine the dissociation constant for the ligand. This constant is used to quickly determine whether a particular ligard is well suited to be considered a potential drug candidate against that protein target.