抄録
Choline acetate, which is one of ionic liquids, was examined for new cryoprotectant using differential scanning calorimetry. High concentration of choline acetate aqueous solutions raised the denaturation temperature of the lysozyme after the minimum at the low concentration. The fragility index and the dynamic glass transition temperature were determined and compared with those of dimethyl sulfoxide and glycerol, which are well known cryoprotectants. The fragility index of choline acetate aqueous solutions with lysozyme was nearly independent to the concentration of choline acetate. The reason was supposed to come from the ionic interaction among lysozyme, water and choline acetate molecules. From the comparison with the known cryoprotectants, choline acetate can be said to be a new good cryoprotectant and the practical experiments should be carried in the future.
