Diffusion Properties of the Ternary System Human Serum Albumin-Sodium Cholate-Water

The four diffusion coefficients of the ternary system human serum albumin (HSA,1)-sodium cholate (NaC,2)-water (W, 0) were determined at three average compositions with constant protein concentration, C-1 degrees, and variable bile salt concentration, C-2. Various types of solute-solute interactions are present in this ternary system: electrostatic, co-ions-protein, and unspecific volume interactions due to the large difference in size of the two solutes. Each type of interaction has a different effect in determining the values and the sign of the experimental diffusion coefficients, D-exp(ij). To simplify the analysis of the dependence of the D-exp(ij) s on C-2, we considered three model systems where different types of solute-solute interaction are present individually. The overall analysis allows highlighting which kinds of solute-solute interaction predominates in determining the value of each diffusion coefficient.