Fujita Kyoko, MacFarlane Douglas R, Forsyth Maria, Yoshizawa-Fujita Masahiro, Murata Kenichi, Nakamura Nobuhumi, Ohno Hiroyuki
Department of Biotechnology, Tokyo University of Agriculture and Technology, Koganei, Tokyo, Japan.
Biomacromolecules. 2007 Jul;8(7):2080-6. doi: 10.1021/bm070041o. Epub 2007 Jun 20.
Hydrated ionic liquids (ILs) were prepared by adding appropriate amounts of water to hydrophilic ILs. Some hydrated ILs show excellent solubilizing ability for proteins, keeping the basic properties of ILs. The solubility of cytochrome c (cyt c) depended on the structure of the component ions. When component anions have oxo acid residues, the resulting hydrated ILs solubilize cyt c quite well. In such hydrated ILs, the structure and activity of cyt c is influenced by the kosmotropicity of the component ions. We synthesized ILs from various ions having different kosmotropicity, including dihydrogen phosphate (dhp), dibutylphosphate, acetate, lactate, and methanesulfonate as anions. The activity of the dissolved cyt c depends on the permutations of kosmotropicity of the component ions. cyt c shows no structural change and retains its activity when dissolved in the hydrated choline dhp, which is an excellent combination of chaotropic cation and kosmotropic anion. Furthermore, cyt c dissolved in the hydrated choline dhp remained in a native state and was active after 18 months of storage at room temperature.
通过向亲水性离子液体（ILs）中加入适量的水来制备水合离子液体。一些水合离子液体对蛋白质表现出优异的溶解能力，同时保持了离子液体的基本性质。细胞色素c（cyt c）的溶解度取决于组成离子的结构。当组成阴离子含有含氧酸残基时，所得的水合离子液体对cyt c的溶解效果相当好。在这类水合离子液体中，cyt c的结构和活性受组成离子的向心性影响。我们从具有不同向心性的各种离子合成了离子液体，包括磷酸二氢根（dhp）、磷酸二丁酯、乙酸根、乳酸根和甲磺酸根作为阴离子。溶解的cyt c的活性取决于组成离子向心性的排列。当溶解在水合胆碱dhp中时，cyt c没有结构变化并保持其活性，水合胆碱dhp是离液序列高的阳离子和向心离子的优异组合。此外，溶解在水合胆碱dhp中的cyt c在室温下储存18个月后仍保持天然状态且具有活性。
