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. Author manuscript; available in PMC: 2014 Mar 1.
Published in final edited form as: J Biomol Screen. 2012 Nov 7;18(4):388–399. doi: 10.1177/1087057112466430

Fig. 2. Intrinsic ATPase activity observed from different sources of purified MEKK2 and used to determine IC50 values for a panel of kinase inhibitors.

Fig. 2

(A) Intrinsic ATPase assay reaction time courses were performed using three different sources of purified MEKK2 obtained from three different vendors: vendor 1(■), vendor 2 (●), and vendor 3 (▲). (B) Concentration response data for sunitinib was normalized to controls with and without enzyme and plotted as percent activity. These IC50 value determinations resulted in average IC50 values of 337, 184, and 315 nM using MEKK2 from vendor 1, 2, and 3, respectively, and average Hill slopes of 1.0 – 1.1 as indicated. (C) Concentration response data for a panel of kinase inhibitors was normalized to controls with and without MEKK2 and plotted as percent activity. Potency determinations for sunitinib (■), dasatinib (●), VX-680 (▼), and staurosporine (◆) resulted in average IC50 values (nM) and SDs of 337 ± 157, 753 ± 268, 3,603 ± 826, 1.0 ± 0.6, respectively. The average Hill slope values derived from the IC50 curves for these compounds ranged from 0.93 – 1.10. Data points represent the average of three determinations per concentration and error bars represent standard deviation. Data are representative of three independent experiments.