Salting-out in the aqueous single-protein solution: the effect of shape factor

A molecular-thermodynamic model is developed to describe salt-induced protein precipitation. The protein-protein interaction goes through the potential of mean force. An equation of state is derived based on the generalized van der Waals partition function. The attractive term including the potential of mean force is perturbed by the statistical mechanical perturbation theory. The precipitation behaviors are studied by calculating the partition coefficient with various conditions such as the ionic strength and the shape of protein. Our results show that the protein shape plays a significant role in the protein precipitation behavior.