title: The solubility and stability of amino acids in biocompatible ionic liquids.
abstract: In recent years, ionic liquids (ILs) represent a new class of biocompatible co-solvents for biomolecules. In this work, we report the apparent transfer free energies (ΔG'tr) for six amino acids (AA) from water to aqueous solutions of six ammonium based ILs (diethylammonium acetate (DEAA), diethylammonium sulfate (DEAS), triethyl ammonium acetate (TEAA), triethylammonium sulfate (TEAS), triethylammonium dihydrogen phosphate (TEAP), and trimethylammonium acetate (TMAA)) through solubility measurements, as a function of IL concentration at 298.15 K under atmospheric pressure. Salting-out effect was found for AA in aqueous IL solutions with increasing IL concentrations. In addition, we observed positive values of ΔG'tr for AA from water to ILs, indicating that the interactions between ILs and AA are unfavorable. From the obtained results, we found that the selected ammonium based ILs act as stabilizers for the structure of AA.
authors.forename: T
authors.initials: T
authors.lastname: Vasantha
authors.forename: Awanish
authors.initials: A
authors.lastname: Kumar
authors.forename: Pankaj
authors.initials: P
authors.lastname: Attri
authors.forename: Pannuru
authors.initials: P
authors.lastname: Venkatesu
authors.affiliation: Department of Chemistry, University of Delhi, Delhi 110 007, India. venkatesup@hotmail.com.
authors.forename: R S Rama
authors.initials: RS
authors.lastname: Devi
mesh_terms: D000596:Amino Acids / Q000737:chemistry*; D064751:Ammonium Compounds / Q000737:chemistry*; D001672:Biocompatible Materials / Q000737:chemistry*; D052578:Ionic Liquids / Q000737:chemistry*; D008958:Models, Molecular; D011487:Protein Conformation; D055550:Protein Stability; D012995:Solubility; D012997:Solvents / Q000737:chemistry
chemical_list: D000596:Amino Acids; D064751:Ammonium Compounds; D001672:Biocompatible Materials; D052578:Ionic Liquids; D012997:Solvents