Dose-dependent modification of engineered cysteines in Panx1 by MBB (A) or MTSET (B). Membrane currents of oocytes expressing Panx1 I60C were attenuated by 10 or 100 µM MBB and by 100 µM or 1 mM MTSET. Both components, the reversible and the irreversible inhibition of the currents, were affected in a dose-dependent way. The reversible component was barely detectable at the lower MBB or MTSET concentrations.