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Updated: Aug 8, 2026

Synthesis of 1,2-Azaborines and the Preparation of Their Protein Complexes with T4 Lysozyme Mutants
Published on: March 25, 2017
Effect of ethanol on folding of hen egg-white lysozyme under acidic condition
Kenji Sasahara1, Katsutoshi Nitta
1Division of Biological Sciences, Graduate School of Science, Hokkaido University, Sapporo, Hokkaido, Japan. sasahara@protein.osaka-u.ac.jp
Abstract:
The equilibrium and kinetics of folding of hen egg-white lysozyme were studied by means of CD spectroscopy in the presence of varying concentrations of ethanol under acidic condition. The equilibrium transition curves of guanidine hydrochloride-induced unfolding in 13 and 26% (v/v) ethanol have shown that the unfolding significantly deviates from a two-state mechanism. The kinetics of denaturant-induced refolding and unfolding of hen egg-white lysozyme were investigated by stopped-flow CD at three ethanol concentrations: 0, 13, and 26% (v/v). Immediately after dilution of the denaturant, the refolding curves showed a biphasic time course in the far-UV region, with a burst phase with a significant secondary structure and a slower observable phase. However, when monitored by the near-UV CD, the burst phase was not observed and all refolding kinetics were monophasic. To clarify the effect of nonnative secondary structure induced by the addition of ethanol on the folding/unfolding kinetics, the kinetic m values were estimated from the chevron plots obtained for the three ethanol concentrations. The data indicated that the folding/unfolding kinetics of hen lysozyme in the presence of varying concentrations of ethanol under acidic condition is explained by a model with both on-pathway and off-pathway intermediates of protein folding.
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