title: Enzymatic catalysis of formation of Z-aspartame in ionic liquid - An alternative to enzymatic catalysis in organic solvents.
abstract: We present the first report of enzymatic catalysis in an ionic liquid. The virtually nonexistent vapor pressure makes ionic liquids an exciting new alternative for enzyme-catalyzed syntheses in environmentally friendly environments. Z-aspartame was synthesized in a thermolysin-catalyzed reaction of carbobenzoxy-L-aspartate and L-phenylalanine methyl ester hydrochloride in 1-butyl-3-methylimidazolium hexafluorophosphate (BP6). Ionic liquids such as BP6 are thermally stable and have a remarkable range of temperatures over which they remain liquid (300 degrees C). With an initial rate of 1.2 +/- 0.1 nmol min(-)(1) mg(-)(1), we observed a competitive rate in comparison to that of enzymatic synthesis in organic solvent. Additionally, the enzyme exhibits outstanding stability, which would normally require immobilization.
authors: Department of Chemical and Petroleum Engineering, Center for Biotechnology and Bioengineering, University of Pittsburgh, Pittsburgh, Pennsylvania 15219, USA. erbeldin+@pitt.edu
authors: M
authors: M
authors: Erbeldinger
authors: A J
authors: AJ
authors: Mesiano
authors: A J
authors: AJ
authors: Russell
mesh_terms: D001218:Aspartame / Q000138:chemical synthesis* / Q000378:metabolism; D002384:Catalysis; D007477:Ions; D007700:Kinetics; D009930:Organic Chemicals / Q000737:chemistry; D012997:Solvents / Q000737:chemistry
chemical_list: D007477:Ions; D009930:Organic Chemicals; D012997:Solvents; D001218:Aspartame