Ion transport through hemocyanin channels in oxidized cholesterol artificial bilayer membranes

Incorporation of molluscan hemocyanins, obtained either from the blood of Megatura crenulata or Paludina vivipara, into oxidized-cholesterol black lipid films results in the formation of ionic channels. Channel conductance depends on the type of electrolyte present, ranging in our experiments from about 20 to 500 pS. It rises in a non-linear way as the salt concentration is increased, showing a saturation effect. An observed pH dependence of channel conductance suggests that there is a negative fixed charge associated with the pore. We discuss a model based on a simplified form of the Gouy-Chapman theory of the electrified double layer to explain the experimental results.