Adsorption of concanavalin A and lentil lectin on platinum electrodes followed by electrochemical impedance spectroscopy: effect of protein state

Adsorption of concanavalin A and lentil lectin on platinum electrode was investigated through electrochemical impedance spectroscopy and cyclic voltammetry. By using ferro/ferricyanide system to probe the electrochemical interface it was possible to model the EIS data with a simple equivalent circuit. The blocking effect for electron transfer reactions observed with these proteins, indicated that they readily adsorb on platinum surface and that the degree of adsorption is related to the state of the proteins. When the proteins are in the presence of divalent cations (Ca²⁺ and Mn²⁺) they adsorb less strongly than in their absence. There is also evidence that at least convanavalin A retains its biological activity in the adsorbed state.