title: Effect of organic cosolvent on kinetic resolution of tert-leucine by penicillin G acylase from Kluyvera citrophila.
abstract: Penicillin G acylase (PGA) from Kluyvera citrophila immobilized on Amberzyml was used for enantioselective hydrolysis of N-phenylacetylated-DL-tert-leucine (N-Phac-DL-Tle) to produce L-tert-leucine (L-Tle). The effects of various organic cosolvents on hydrolysis of N-Phac-DL-Tle have been investigated in aqueous-cosolvent medium. It was founded that the rate of PGA-catalyzed reaction was significantly affected by the presence of 2% (v/v) organic cosolvent concentration. The initial rate fell with increasing logP of the cosolvent, but for logP values less than -0.24 the rate was faster than in purely aqueous medium. Additionally, the relative rate increases with the increase of dielectric constant (epsilon) of organic cosolvents. The yields of L-Tle in all aqueous-cosolvent systems were above 95% with the enantiomeric excess (ee) of >99%.
authors.affiliation: State Key Lab of Bioreactor Engineering, East China University of Science and Technology, 130 Meilong Road, Shanghai, 200237, People's Republic of China.
authors.forename: Shu-Lai
authors.initials: SL
authors.lastname: Liu
authors.forename: Dong-Zhi
authors.initials: DZ
authors.lastname: Wei
authors.forename: Qing-Xun
authors.initials: QX
authors.lastname: Song
authors.forename: Ye-Wang
authors.initials: YW
authors.lastname: Zhang
authors.forename: Xue-Dong
authors.initials: XD
authors.lastname: Wang
mesh_terms: D004789:Enzyme Activation; D004800:Enzymes, Immobilized / Q000737:chemistry; D007700:Kinetics; D044086:Kluyvera / Q000201:enzymology*; D007930:Leucine / Q000031:analogs & derivatives; D009930:Organic Chemicals / Q000737:chemistry*; D010399:Penicillin Amidase / Q000737:chemistry*; D012997:Solvents / Q000737:chemistry*; D014633:Valine / Q000031:analogs & derivatives* / Q000737:chemistry
chemical_list: D004800:Enzymes, Immobilized; D009930:Organic Chemicals; D012997:Solvents; C089871:2-amino-3,3-dimethylbutanoic acid; D010399:Penicillin Amidase; D007930:Leucine; D014633:Valine