Characterization of cyanide binding to cytochrome c oxidase immobilized in electrode-supported lipid bilayer membranes

Bovine cytochrome c oxidase has been successfully immobilized in electrode-supported lipid bilayer membranes to investigate the effect of cyanide binding on the oxidation of ferrocytochrome c and the electroreduction of dioxygen. Cyanide binding to oxidase was found to be reversible and exhibited 1:1 stoichiometry. Binding constants (Ki) were also determined for binding of cyanide to the reduced (62 μM) and oxidized (195 μM) forms of the oxidase. The cytochrome c oxidase-modified electrodes described here could potentially be used as an amperometric biosensor for the detection of cyanide.