Figure 5
Phosphatase activity of PTPN4 bidomain constructs mutated in the linker. (a) Michaelis-Menten plots of initial rates of pNPP hydrolysis by different PTPN4 proteins at 600 nM without PDZ ligand; (b) Michaelis-Menten plots of initial rates of pNPP hydrolysis by different PTPN4 proteins at 600 nM in the presence of a saturated concentration of PDZ ligand (70–100 μM of Cyto8-RETEV); 
linker-PTP; 
PDZ-PTPWT; 
F620G; 
Q621G; 
Y622G; 
I623G. The solid lines are nonlinear least-squares fits of the data to the Michaelis-Menten equation. (c) kcat of PTPN4 constructs in the absence of PDZ ligand (light grey) and in the presence of PDZ ligand (Cyto8-RETEV) (dark grey). (d) KM of PTPN4 constructs in the absence of PDZ ligand (light grey) and in the presence of PDZ ligand (Cyto8-RETEV) (dark grey).
