title: Studies on the isolation of penicillin acylase from Escherichia coli by aqueous two-phase partitioning.
abstract: A method of enzyme release and aqueous two-phase extraction is described for the separation of penicillin acylase from Escherichia coli cells. Butyl acetate, 12% (v/v), treatment combined with freeze-thawing gives up to 70% enzyme release. For polyethylene glycol (PEG) + phosphate two-phase extraction systems the enzyme purity and yield were rather low. Modified PEG, including PEG-ampicillin, PEG-aniline, PEG-phosphate, and PEG-trimethylamine, were synthesized and used in aqueous two-phase systems; PEG-trimethylamine is the most satisfactory. A system containing 12% (w/w) PEG4000, 8% (w/w) of which is PEG-trimethylamine, with 0.7M potassium phosphate at pH 7.2, resulted in the enzyme selective partition being greatly enhanced by charge directed effects. Possible mechanisms for the separation process are discussed.
authors.affiliation: Department of Biochemical Engineering, East China University of Chemical Technology, Shanghai 200237, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Guan
authors.forename: X Y
authors.initials: XY
authors.lastname: Wu
authors.forename: T E
authors.initials: TE
authors.lastname: Treffry
authors.forename: T H
authors.initials: TH
authors.lastname: Lilley