A determination of the reduction potentials for diferric and C- and N-lobe monoferric transferrins at endosomal pH (5.8)

An investigation was conducted to determine the formal redox potential of the Fe in FeCTf, FeNTf and Fe2Tf at endosomal pH of 5.8. An optically transparent thin-layer electrochemical cell and a spectroelectrochemical technique were utilized. Results showed the redox properties of two sites are similar and the redox potentials are too negative for a reductive mechanism to be involved in the endosomal release of Fe from transferrin without coupling to a cascade of reactions which include chelation of Fe.