Next, a displacement titration (Figure , right column) was carried out. For this purpose, the protein (c = 20 µM) was incubated with the fragment (c = 4.2 mM) prior to the titration with strong binding fasudil (c = 300 µM), the displacing ligand. The differences in the thermodynamic profiles of PKA and fasudil and in the displacement titration are so small that they are within the error of the experiments.