The heterogeneous electron transfer of cytochrome c adsorbed on Ag electrodes coated with omega-carboxyl alkanethiols. A surface enhanced resonance Raman spectroscopic study

Cytochrome c adsorbed on Ag electrodes coated with self-assembled monolayer s of carboxyl-terminated alkanethiols was studied by surface enhanced reson ance Raman spectroscopy. Potential-dependent measurements indicate that the bound protein can adopt different orientations depending on protein-protei n interactions and anion binding. At high protein coverage or in the presen ce of specifically adsorbed anions the heterogeneous distribution of orient ations is responsible for the apparent non-ideal electrochemical behaviour. (C) 2001 Elsevier Science B.V. All rights reserved.