LIGHT-SCATTERING OF BOVINE SERUM-ALBUMIN SOLUTIONS - EXTENSION OF THE HARD PARTICLE MODEL TO ALLOW FOR ELECTROSTATIC REPULSION

The light scattering of bovine serum albumin (BSA) was measured at protein concentration up to 90 g/l and at pH values between 4.4 and 7.6 The dependence of scattering on both protein concentration and pH may be quantitatively accounted for by a simple extension of the hard-sphere model for protein solutions allowing for electrostatic repulsions between molecules. According to the extended model, the radius of the effective hard spherical particle representing BSA varies with the net electrical charge of the BSA molecule in a manner which may be calculated from electrostatic theory.