Abstract
Crystallization kinetics of two polymorphs, tetragonal and orthorhombic forms, of hen egg white lysozyme was examined with optical method. An induction time for crystallization of each crystal was measured at different crystallization conditions (temperature, pH, concentration of three precipitants of NaCl, (NH_4)_2SO_4 and NH_4 Cl). The occurrence behavior of the two polymorphs was primarily influenced by temperature and pH, irrespective of the precipitants employed. The rate of crystallization, however, was remarkably affected by the precipitants. After examining the moderate rate of crystallization, we obtained large-size single crystals; 〜0.5 mm for tetragonal form and 〜5 mm for orthorhombic form.
