Kinetics of K ⁺ -current activation. (A) The activating current displayed two kinetic components, hereafter “fast” (teal arrow) and “slow” (orange arrow). (B) Also, the activation displayed a lag phase (green arrow). To accommodate these features, an n-powered double exponential function (red traces) was fitted to these activating K⁺-currents (black traces). (C) The index n was different between WT and the mutant R198H, yet, it also seemed impervious to changes in pH_EXT. (D and G) Average time constant of the fast component (τ_FAST) as a function of the activating potential (V_ACT) for both WT and R198H (n = 5, each). (E and H). Average time constant as a function of the activating potential (V_ACT) for the slow component (τ_SLOW) for both WT and R198H (n = 5, each). (F and I) Fraction of the fast component for the activation process for both WT and R198H (n = 5, each). Statistical test performed using pH_EXT 7.4 as reference. T test confidences are color coded.