Fig. 4. Recovery of iCP activity in the rapid dilution assay. To a 100-fold concentration of iCP used in the kinetic assay, a 10-fold IC₅₀ concentration of the selected inhibitor (either 45 nM DPLG-3 or 1060 nM compound 47) was added. The reaction mix was immediately (0 min), or after pre-incubation (30 min), diluted 100-fold with the substrate. For the reversible inhibitor DPLG-3 (A), almost a full recovery of iCP activity was observed, while in the case of compound 47 (B) only a 22% recovery was observed, indicating the irreversible mode of inhibition.