“…As shown elsewhere, the enthalpic stabilization of the reduced state is due to the hydrophobic environment and the low solvent accessibility of the metal center; the negative value of DS 0 rc , which favors the oxidized state, is indeed typical of buried metal centers [35,46,48]. It is well-documented [1,22,23,46,49] that E°0 and the DS 0 rc and DH 0 rc values for freely diffusing proteins are influenced by the nature and concentration of the electrolyte(s) in solution. The data reported in Table 1 show that this is also the case for adsorbed pc, whose reduction thermodynamics turns out to be affected by the ionic strength of the solution in contact with the electrode surface.…”