Electrostatic potential of mean force between charged bovine serum albumin molecules in aqueous NaCl solutions by hypernetted-chain integral equation

Abstract

The electrostatic potentials of mean force between charged bovine serum albumin (BSA) molecules at different NaCl and BSA concentrations are obtained by solving the hypernetted-chain integral equations. From the results, a short-range attractive force between the same charged BSA molecules is found at low BSA valences or high NaCl concentrations. Comparisons have been made with the Derjaguin–Landau–Verwey–Overbeek (DLVO) theory and the Sogami–Ise (SI) theory. In aqueous BSA–NaCl solution, the DLVO theory is much more accurate than SI theory at low concentration as 0.15 mol/L, but they both failed in high salt concentrations such as 1.0 and 3.0 mol/L. The electrostatic interaction range shortens with the increase of salt concentration. The electrostatic repulsion between colloidal particles may be weakened by the increase of charges on macro-ions in certain charge range in high salt concentration. The influence of charged BSA concentrations on the electrostatic potential of mean force is also given. The electrostatic potentials of mean force between charged BSA molecules oscillate with the increase of its concentrations.