title: Poly(ethylene glycol)-lipase complexes that are highly active and enantioselective in ionic liquids.
abstract: Lipase-catalyzed alcoholysis between vinyl acetate and 2-phenyl-1-propanol was investigated in dialkylimidazolium-based ionic liquids. Although native lipase powder exhibited very low activity in an ionic liquid, forming a poly(ethylene glycol)(PEG)-lipase complex improved the lipase activity in the ionic liquid. The activity of the PEG-lipase complex was higher in ionic liquids than in common organic solvents (n-hexane, isooctane and dimethylsulfoxide). Fluorescence measurements using 4-aminophthalimide revealed that the ionic liquids were more hydrophilic than the organic solvents used for non-aqueous enzymology. A kinetic study of lipase-catalyzed alcoholysis in an ionic liquid ([Bmim][PF6]) revealed that the Michaelis constant (Km) for 2-phenyl-1-propanol in the ionic liquid was half that in n-hexane, suggesting that the ionic liquid stabilized the enzyme-substrate complex. Finally, we carried out enantioselective alcoholysis of 1-phenylethanol in ionic liquids employing the PEG-lipase complex, and obtained high enantioselectivity, comparable to that in n-hexane.
authors.affiliation: Department of Applied Chemistry, Graduate School of Engineering, Kyushu University and PRESTO, JST, 6-10-1 Hakozaki, Fukuoka 812-8581, Japan.
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Maruyama
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Yamamura
authors.forename: Takahiro
authors.initials: T
authors.lastname: Kotani
authors.forename: Noriho
authors.initials: N
authors.lastname: Kamiya
authors.forename: Masahiro
authors.initials: M
authors.lastname: Goto
mesh_terms: D001665:Binding Sites; D002384:Catalysis; D006586:Hexanes / Q000737:chemistry; D057927:Hydrophobic and Hydrophilic Interactions; D007477:Ions; D007700:Kinetics; D008049:Lipase / Q000737:chemistry* / Q000378:metabolism; D008970:Molecular Weight; D011092:Polyethylene Glycols / Q000737:chemistry*; D020005:Propanols / Q000737:chemistry; D012997:Solvents / Q000737:chemistry*; D013237:Stereoisomerism; D013379:Substrate Specificity; D013696:Temperature; D014753:Vinyl Compounds / Q000737:chemistry; D014867:Water / Q000737:chemistry
chemical_list: D006586:Hexanes; D007477:Ions; D020005:Propanols; D012997:Solvents; D014753:Vinyl Compounds; D014867:Water; C439395:1-phenylpropanol; C026385:n-hexane; D011092:Polyethylene Glycols; D008049:Lipase; C011566:vinyl acetate