Possibility of Ionic Liquid for a New Preservation Agent : Structural Stability of Protein in Ionic Liquid-Water Mixed Solutions

Abstract

We have investigated the additive effect of 1-butyl-3-methylimidazolium acetate ([bmim][acetate]), which is one of the imidazolium-based ionic liquid (IL), on the stability of secondary structure of lysozyme in water by the use of FT-IR spectroscopy. From the IR spectral analyses, we found that the population of the α-helical structure of lysozyme decreases up to 6 M. However, the population of the α-helical structure at 10 M is higher than that at 6 M. This result means that the degree of protein unfolding becomes smaller above 6 M. Our result shows that [bmim][acetate] has a possibility for a new preservation agent.