Figure 4.
Steady-state fluorescence change of Ub-AMC and K48-linked IQF diubiquitin binding to C276A USP2. (A) The fluorescence change of 0.5 μM Ub-AMC was plotted against increasing concentrations of USP2 (0-25 μM). (B) The fluorescence change of 25 nM K48-linked IQF diubiquitin was recorded with increasing concentrations of USP2 (0-8 μM). The apparent dissociation constant was determined through nonlinear curve fitting to equation 1 using GraphPad Prism.