title: Aqueous two-phase system based on natural quaternary ammonium compounds for the extraction of proteins.
abstract: Aqueous two-phase systems, based on the use of natural quaternary ammonium compounds, were developed to establish a benign biotechnological route for efficient protein separation. In this study, aqueous two-phase systems of two natural resources betaine and choline with polyethyleneglycol (PEG400/600) or inorganic salts (K2 HPO4 /K3 PO4 ) were formed. It was shown that in the K2 HPO4 -containing aqueous two-phase system, hydrophobic interactions were an important driving force of protein partitioning, while protein size played a vital role in aqueous two-phase systems that contained polyethylene glycol. An extraction efficiency of more than 90% for bovine serum albumin in the betaine/K2 HPO4 aqueous two-phase system can be obtained, and this betaine-based aqueous two-phase system provided a gentle and stable environment for the protein. In addition, after investigation of the cluster phenomenon in the betaine/K2 HPO4 aqueous two-phase systems, it was suggested that this phenomenon also played a significant role for protein extraction in this system. The development of aqueous two-phase systems based on natural quaternary ammonium compounds not only provided an effective and greener method of aqueous two-phase system to meet the requirements of green chemistry but also may help to solve the mystery of the compartmentalization of biomolecules in cells.
authors.affiliation: College of Light Industry and Food Sciences, South China University of Technology, Guangzhou, China.
authors.forename: Chao-Xi
authors.initials: CX
authors.lastname: Zeng
authors.affiliation: College of Light Industry and Food Sciences, South China University of Technology, Guangzhou, China.
authors.forename: Rui-Pu
authors.initials: RP
authors.lastname: Xin
authors.affiliation: College of Light Industry and Food Sciences, South China University of Technology, Guangzhou, China.
authors.forename: Sui-Jian
authors.initials: SJ
authors.lastname: Qi
authors.affiliation: School of Bioscience and Bioengineering, South China University of Technology, Guangzhou, China.
authors.forename: Bo
authors.initials: B
authors.lastname: Yang
authors.affiliation: College of Light Industry and Food Sciences, South China University of Technology, Guangzhou, China.
authors.forename: Yong-Hua
authors.initials: YH
authors.lastname: Wang
mesh_terms: D064751:Ammonium Compounds / Q000737:chemistry; D000818:Animals; D001622:Betaine / Q000737:chemistry; D002417:Cattle; D005591:Chemical Fractionation / Q000379:methods*; D002794:Choline / Q000737:chemistry; D002942:Circular Dichroism; D055772:Green Chemistry Technology; D057927:Hydrophobic and Hydrophilic Interactions; D008027:Light; D046911:Macromolecular Substances / Q000737:chemistry; D009113:Muramidase / Q000737:chemistry; D010047:Ovalbumin / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D011506:Proteins / Q000737:chemistry* / Q000302:isolation & purification; D000644:Quaternary Ammonium Compounds / Q000737:chemistry*; D012492:Salts / Q000737:chemistry; D012542:Scattering, Radiation; D012710:Serum Albumin, Bovine / Q000737:chemistry; D014357:Trypsin / Q000737:chemistry; D014867:Water
chemical_list: D064751:Ammonium Compounds; D046911:Macromolecular Substances; D011506:Proteins; D000644:Quaternary Ammonium Compounds; D012492:Salts; D014867:Water; D012710:Serum Albumin, Bovine; D001622:Betaine; D011092:Polyethylene Glycols; D010047:Ovalbumin; D009113:Muramidase; D014357:Trypsin; D002794:Choline
keywords: Aqueous two-phase systems; Protein separation; Quaternary ammonium compounds