Pore-forming (alpha) subunit of a voltage-gated delayed rectifier potassium channel that mediates outward-rectifying potassium currents. Elicits a slowly activating, non-inactivating and slowly deactivation outwards potassium current at depolarizating voltages from -30 mV to +50mV. Shows no obvious change in the activation rate from different holding potentials. Activation is strongly dependent on the pH of the external solution 