The nature of the voltage-dependent conductance of the hemocyanin channel

The electrical responses of individual hemocyanin channels in oxidized cholesterol membranes demonstrate that the voltage-dependent conductance of many-channel membranes arises from two different mechanisms. These are the voltage-dependent redistribution of channels among several discrete single-channel conductance states and the continuously voltage-dependent conductance of the single-channel states themselves. The relaxation time for the discrete conductance changes is of the order of seconds and the relaxation time of the continuous conductance changes is of the order 10^-4 seconds. As salt concentration in the bathing medium is increased, the single-channel conductance first increases linearly and then saturates. The characteristics of the saturation curves suggest that the continuous conductance changes occur at the edges of the channel and that the mean time an ion spends in the channel is 4 nanoseconds.