Abstract Here we have studied the kinetics as well as the energetics of a diffusion influenced nonequilibrium gating process of a voltage-gated K-channel for a oscillatory voltage through the master equation description. A diffusion-influenced five-state Hodgkin-Huxley type voltage-gated scheme is proposed on the basis of the established findings that the K-ions can diffuse through a mutated voltage sensing domain even if the channel protein remains in the closed conformation. At moderate frequencies of the oscillatory voltage, the dynamic hysteresis behaviour shown by the kinetic and thermodynamic response properties of this channel protein are annihilated by the diffusion of K-ions at diffusion controlled limit. Moreover, for oscillating voltage the diffusion time scale interferes with the intrinsic time scale of the ion-channel producing a beating phenomenon in the current signal whose modulation depth depends on the diffusion rate. At reaction-controlled limit, the time periodic oscillation of the total entropy production rate shows the symmetric behaviour over the two half cycles at extreme high frequencies, but at diffusion-controlled limit such symmetry is destroyed.
Keywords Voltage gated K channel; mutated voltage sensing domain; diffusion influenced gating; nonequilibrium thermodynamics; dynamical hysteresis.