Solubility and Stability of Cytochrome c in Hydrated Ionic Liquids:  Effect of Oxo Acid Residues and Kosmotropicity

Abstract

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.

Task Specific Ionic Liquids for Cellulose Technology

“…[5][6][7] There is also an increasing number of studies on bio-catalytic reactions. 8,9 Solubilization of enzymes, and enzymatic reactions in ILs, [10][11][12] aqueous ILs, 13 or hydrated ILs 14 have been demonstrated in recent years with the aim of preparing a suitable matrix for enzymes. However, there has been little study of ILs to dissolve enzymes.…”

Physicochemical and Acid-base Properties of a Series of 2-Hydroxyethylammonium-based Protic Ionic Liquids

“…[19][20][21][22] In addition, they act as solvents or catalysts for various organic reactions. 23,24 Similarly, RTILs with the hydroxyl groups have CO2 absorption, [25][26][27][28][29] and cellulose/protein dissolution abilities.…”

Probing the specific ion effects of biocompatible hydrated choline ionic liquids on lactate oxidase biofunctionality in sensor applications

“…Several studies have revealed that the best stabilising conditions are normally provided by chaotropic cations and kosmotropic anions. [36][37][38][39] Choline is well known as a chaotropic cation for the stabilisation of proteins when coupled with a kosmotropic anion, such as DHP. 37 According to the Hofmeister anion series, DHP is considered a stabilising anion, while nitrate and chloride anions are normally considered as strong and slightly destabilising anions, respectively.…”