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Crystallization of Hen Egg White Lysozyme by Solvent Freeze‐Out: Effect of Cooling Rate on Protein Inclusion in the Ice Layer
Author(s) -
Ryu B.H.,
Jones M. J.,
Ulrich J.
Publication year - 2010
Publication title -
chemical engineering and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.403
H-Index - 81
eISSN - 1521-4125
pISSN - 0930-7516
DOI - 10.1002/ceat.201000130
Subject(s) - crystallization , supersaturation , lysozyme , protein crystallization , dissolution , chemistry , solvent , salt (chemistry) , nucleation , egg white , aqueous solution , crystallography , chemical engineering , chromatography , solubility , biochemistry , organic chemistry , engineering
A new technique for crystallizing proteins is introduced. Solvent removal by freezing‐out is employed to crystallize hen egg white lysozyme from aqueous salt solutions. The crystallization is carried out at moderate salt concentrations (1–10 wt % NaCl) and at pH 4.4–5.2. The required supersaturation for nucleation and crystal growth is achieved by removal of the solvent resulting in a concentration increase with respect to salt, buffer, and protein. A simple tube and shell heat exchanger is used to generate the driving force for crystallization of the ice. The enzymatic activity of the resulting crystals is measured after their dissolution and shows large variations with respect to the crystallization conditions, though no systematic behavior is observed. The effect of the cooling rate applied to the cold finger upon the protein concentration in the ice is investigated.