Fig. 3.

Dose–response curves. Phosphatase activity was measured at 37 °C in the presence of inhibitors as initial velocity and was related to independent 100% and 0% controls. The resulting percent activity is shown vs. inhibitor concentrations. The data were fitted to the four-parameter logistic model (4PL) and to the models A6, N6, and C6. a The phosphatase VHR was inhibited with compound 281. The Hill coefficient was 2.7. Other parameters obtained from fitting are shown in row 1,282 of table FitANCH6.xls of the supplementary material. The green (…-) dotted line does not result from data fitting but illustrates the case of simple competitive binding (C1), with IC50 taken from 4PL. Models A6, N6, and C6 could fit the data equally well for Hill coefficients ≥1. b The phosphatase VE-PTP was inhibited with compound 172. The Hill coefficient was 0.55. Other parameters obtained from fitting are shown in row 1,182 of table FitANCH6.xls of the supplementary material. Model A6 (not C6 or N6) could fit the data when the Hill coefficient was significantly smaller than 1