Two proton-one electron coupled transfer in iron and manganese superoxide dismutases: A density functional study

DFT study of FeSOD and MnSOD enzymes: an inner sphere mechanism has been elucidated for the oxidative step in disproportionation of superoxide anion catalyzed by FeSOD and MnSOD. An analysis of the transfer processes shows that a complex concerted transfer involving two protons and one electron is a key step in the mechanism. The crucial role of the metal-coordinated water molecule in the catalytic reaction is stated. From a comparison between the theoretical results and the experimental data, several complexes have been proposed as inactive species.