A typical plot of polarization versus ligand/protein ratio is shown below:
In this experiment, 1 micromolar mant-GTPgS (a fluorescent, non-hydrolyzable GTP analog) was present and the concentration of the GTP-binding protein, dynamin, was varied by starting at high concentrations followed by dilution.  The binding curve was fit to the anisotropy equation (in this case the yield of the fluorophore increased about 2 fold upon binding).  A Kd of 8.3 micromolar was found
Polarization in Protein V