Dynamic protein clusterization in supercritical region of the phase diagram of water-protein-salt solutions

作者：Rozhkov S P^*; Goryunov A S

来源：Journal of Supercritical Fluids, 2014, 95: 68-74.

DOI：10.1016/j.supflu.2014.07.028

• Protein clusters
• Phase diagrams
• Thermodynamic stability
• (Quasi)Spinodal
• Critical point

A protein solution phase diagram, constructed on the basis of the thermodynamic description of protein solvent interaction, is discussed. A thermodynamic mechanism of formation of protein clusters-oligomers and mesoscopic clusters in the supercritical region of a protein solution phase diagram, is considered. Variation in the chemical potential of water, which depends on solution composition, is the parameter which describes the interaction. Equations for the spinodal and critical points of the phase diagram, in which the critical composition (protein to salt concentration ratio) of the system is related to the physico-chemical characteristics of protein (charge, number of adsorbed ions) and salt (activity), are proposed. The equations are used to construct the phase diagrams of protein solution in the water chemical potential, protein and salt concentration planes, protein solubility and salt concentration plane and to relate effective temperature and critical composition at which a critical point and a spinodal are achieved. The approach proposed provides a deeper insight into the formation of globular-reticular and cellular structures in water protein solution, induced by phase transformation in the pre-critical and in the supercritical region of the phase diagram.

• 出版日期2014-11