Electrochemistry and Catalysis by Myoglobin in Surfactant Films

The electrochemical response of myoglobin and its metal-substituted or chemically modified derivatives is greatly enhanced when contained within surfactant films on electrode surfaces. The aqueous electrochemistry of such myoglobin-films is similar to that of Fe-porphyrins in organic solvents in that both FeIII/II and FeII/I couples are chemically reversible, but aqueous phase ligands readily interact with the Fe site. Sequential and rapid scanning voltammetry yield dynamic electrochemistry indicative of gating of electron transfer by ligand dissociation and active site rearrangement. These myoglobin/surfactant films have biomimetic nitrite-, sulfite- and oxido-reductase activity. Initial investigations into nitrite reductions catalyzed by the myoglobin-films are described. A nitroxyl intermediate. FeII-NO−, is the likely branching point between different pathways forming NH3 and N2O