On the relationship between the solubility of proteins and the osmotic second virial coefficient

Abstract

A relationship between the osmotic second virial coefficient of proteins in aqueous salt solutions, the solubility of proteins in these solutions and the salt concentration is presented. The model developed considers that the solid-liquid equilibrium is established with neutral protein molecules and that the relationship between the protein solubility and the salt concentration follows Cohn's equation. The validity of the model is restricted to the salting-out region of the phase diagrams, which is the situation of greater practical importance. The resulting equations were successfully applied to systems containing lysozyme and ovalbumin.