Steady-state activation and current kinetics of A780P. Voltage dependence of steady-state activation (A) and time constants of activation and deactivation (B) of mutant A780P. Solid lines show simulations based on the rate constants x(V) and y(V) of Table III. Voltage dependence of the activation time constants (B) was not reproduced under the assumption of x(V) and y(V) being identical for all mutants. Dotted lines show improved simulations for A780P obtained by individual fits of x(V) and y(V) (see Table IV).