Fig. 6.

Isothermal titration calorimetry of 25 μM of the phosphatase VHR with compound 281. A solution of 1 mM compound 281 was titrated in 8 μl steps into a solution of VHR phosphatase at 37 °C. The heat absorbed/released upon their interaction (ΔH) was monitored over time (top panel). The heats from each injection is integrated and plotted against the ratio of compound 281 and VHR phosphatase in the cell (closed squares). These data were fitted with model C6 and equilibrium constants from inhibition experiments (blue solid line), C6 without restriction (red dashed line), and model C2 (green dotted line). The parameters obtained from the fitting procedures were compiled in a table shown in the supplementary material. The binding mechanism deduced indirectly from Fig. 3a thus could be confirmed with direct measurements