title: Ucon-benzoyl dextran aqueous two-phase systems: protein purification with phase component recycling.
abstract: Benzoyl dextran with a degree of substitution of 0.18 was synthesized by reacting dextran T500 with benzoyl chloride. A new type of aqueous two-phase system composed of benzoyl dextran as bottom phase polymer and the random copolymer of ethylene oxide and propylene oxide (Ucon 50-HB-5100) as top phase polymer has been formed. The phase diagram for the system Ucon 50-HB-5100-benzoyl dextran with a degree of substitution of 0.18 was determined at room temperature. This two-phase system has been used to purify 3-phosphoglycerate kinase from baker's yeast. The top-phase polymer (Ucon) can be separated from target enzyme by increasing the temperature. The bottom-phase polymer (benzoyl dextran) could be recovered by addition of salt. Yeast homogenate was partitioned in a primary Ucon 50-HB-5100-benzoyl dextran aqueous two-phase system. After phase separation the top phase was removed and temperature-induced phase separation was used for formation of a water phase and a Ucon-rich phase. The benzoyl dextran-enriched bottom phase from the primary system was diluted, and the polymer was separated from water by addition of Na2SO4.
authors.affiliation: Department of Biochemistry, University of Lund, Sweden.
authors.forename: M
authors.initials: M
authors.lastname: Lu
authors.forename: P A
authors.initials: PA
authors.lastname: Albertsson
authors.forename: G
authors.initials: G
authors.lastname: Johansson
authors.forename: F
authors.initials: F
authors.lastname: Tjerneld
mesh_terms: D003911:Dextrans / Q000737:chemistry*; D004852:Epoxy Compounds / Q000737:chemistry*; D009994:Osmolar Concentration; D010735:Phosphoglycerate Kinase / Q000737:chemistry*; D011095:Polyethylenes; D011108:Polymers / Q000737:chemistry*; D011126:Polypropylenes; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000201:enzymology*; D012492:Salts / Q000737:chemistry; D013431:Sulfates / Q000737:chemistry; D013696:Temperature; D014867:Water / Q000737:chemistry*
chemical_list: D003911:Dextrans; D004852:Epoxy Compounds; D011095:Polyethylenes; D011108:Polymers; D011126:Polypropylenes; D012492:Salts; D013431:Sulfates; D014867:Water; C012036:sodium sulfate; C078661:UCON 50-HB-5100; D010735:Phosphoglycerate Kinase