Target-specific inhibition of Lyp-CCPGCC. (A) WT Lyp (2.5 µM) or (B) Lyp-CCPGCC (2.5 µM) was incubated in the absence (closed circles) or presence of FlAsH (10 µM, open circles), diluted, and assayed for activity with the PTP substrate pNPP at the indicated concentrations. C) Concentration-dependence of FlAsH-induced inhibition: Wild-type Lyp (250 nM, closed circles) or Lyp-CCPGCC (250 nM, open circles) was incubated in the absence or presence (indicated concentrations) of FlAsH. The resulting solutions were assayed for activity with pNPP (9 mM). “% PTP Activity” is defined as the initial velocity in the presence of FlAsH divided by the initial velocity of the vehicle-only (100%) control.