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Solid–liquid equilibria for solutions of binary globular‐protein mixtures
Author(s) -
Hino Toshiaki,
Prausnitz John M.
Publication year - 1999
Publication title -
aiche journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.958
H-Index - 167
eISSN - 1547-5905
pISSN - 0001-1541
DOI - 10.1002/aic.690450319
Subject(s) - globular protein , van der waals force , thermodynamics , chemistry , binary number , hard spheres , crystallization , solubility , physics , crystallography , mathematics , organic chemistry , molecule , arithmetic
A theory of the van der Waals form is used to establish solid–fluid phase diagrams for aqueous solutions containing two kinds of globular proteins. Theory is based on a one‐fluid model that uses a composition‐dependent hard‐sphere diameter and a composition‐dependent solvent‐mediated effective temperature to represent protein solutions. The hard‐sphere reference equation of state is based on the model of Young that correlates computer simulations of fluid–solid coexistence curves for binary hard‐sphere mixtures. The attractive perturbation term uses the inverse‐power potential with variable exponent n. Based on the correlation of George and Wilson and Rosenbaum et al., the optimum range of effective temperature is determined for protein crystallization. For binary protein systems, as the size difference increases, the mutual solubility of unlike proteins declines sharply in the precipitated solid phase. The theoretical results obtained here may be useful for design of protein‐separation processes by crystallization.