title: Design of functional guanidinium ionic liquid aqueous two-phase systems for the efficient purification of protein.
abstract: A series of novel cationic functional hexaalkylguanidinium ionic liquids and anionic functional tetraalkylguanidinium ionic liquids have been devised and synthesized based on 1,1,3,3-tetramethylguanidine. The structures of the ionic liquids (ILs) were confirmed by (1)H nuclear magnetic resonance ((1)H NMR) and 13C nuclear magnetic resonance (13C NMR) and the production yields were all above 90%. Functional guanidinium ionic liquid aqueous two-phase systems (FGIL-ATPSs) have been first designed with these functional guanidinium ILs and phosphate solution for the purification of protein. After phase separation, proteins had transferred into the IL-rich phase and the concentrations of proteins were determined by measuring the absorbance at 278 nm using an ultra violet visible (UV-vis) spectrophotometer. The advantages of FGIL-ATPSs were compared with ordinary ionic liquid aqueous two-phase systems (IL-ATPSs). The proposed FGIL-ATPS has been applied to purify lysozyme, trypsin, ovalbumin and bovine serum albumin. Single factor experiments were used to research the effects of the process, such as the amount of ionic liquid (IL), the concentration of salt solution, temperature and the amount of protein. The purification efficiency reaches to 97.05%. The secondary structure of protein during the experimental process was observed upon investigation using UV-vis spectrophotometer, Fourier-transform infrared spectroscopy (FT-IR) and circular dichroism spectrum (CD spectrum). The precision, stability and repeatability of the process were investigated. The mechanisms of purification were researched by dynamic light scattering (DLS), determination of the conductivity and transmission electron microscopy (TEM). It was suggested that aggregation and embrace phenomenon play a significant role in the purification of proteins. All the results show that FGIL-ATPSs have huge potential to offer new possibility in the purification of proteins.
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China.
authors.forename: Xueqin
authors.initials: X
authors.lastname: Ding
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China. Electronic address: wyzss@hnu.edu.cn.
authors.forename: Yuzhi
authors.initials: Y
authors.lastname: Wang
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China.
authors.forename: Qun
authors.initials: Q
authors.lastname: Zeng
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China.
authors.forename: Jing
authors.initials: J
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China.
authors.forename: Yanhua
authors.initials: Y
authors.lastname: Huang
authors.affiliation: State Key Laboratory of Chemo/Biosensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha 410082, PR China.
authors.forename: Kaijia
authors.initials: K
authors.lastname: Xu
mesh_terms: D000818:Animals; D002417:Cattle; D002852:Chromatography, Ion Exchange; D002942:Circular Dichroism; D006146:Guanidines / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D052578:Ionic Liquids / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D008027:Light; D009113:Muramidase / Q000737:chemistry / Q000302:isolation & purification; D010047:Ovalbumin / Q000737:chemistry / Q000302:isolation & purification; D017433:Protein Structure, Secondary; D011506:Proteins / Q000737:chemistry / Q000302:isolation & purification*; D012542:Scattering, Radiation; D012710:Serum Albumin, Bovine / Q000737:chemistry / Q000302:isolation & purification; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D013696:Temperature; D014357:Trypsin / Q000737:chemistry / Q000302:isolation & purification; D014867:Water / Q000737:chemistry
chemical_list: D006146:Guanidines; D052578:Ionic Liquids; D007477:Ions; D011506:Proteins; D014867:Water; D012710:Serum Albumin, Bovine; D010047:Ovalbumin; D009113:Muramidase; D014357:Trypsin; C477069:1,1,3,3-tetramethylguanidine
keywords: Aggregation; Functional guanidinium ionic liquid; Functional guanidinium ionic liquid aqueous two-phase systems; Protein; Purification