“…One model type of interest is that considering the ''inverse problem'' [17] where, for a given protocol involving wellspecified bulk pH, ionic strength I, temperature T, electrical permittivity e and viscosity Z of the BGE, the experimental effective mobility is provided as the basic data to evaluate analyte properties such as, for instance, hydration, effective electrical charge, hydrodynamic size and shape, and pH-microenvironment, among others. This basic problem has associated the charge regulation phenomenon, also designated proton-binding cooperativity, which is always present around electrophoretically migrating particles [15][16][17][18][19][20][21][22][23][24]. This phenomenon is relevant to estimate the protein pK-shifts of the i-ionizing group designated DpK i , the pH near molecule pH Ã , and the pH near the i-ionizing group indicated as pH i , for i 5 1yN c .…”