Chemical modification for improving activity and stability of lipase B from Candida antarctica with imidazolium-functional ionic liquids.
Various imidazolium-functional ionic liquids (ILs) composed of different cations and anions were grafted onto Candida antarctica lipase B (CALB) through lysine coupling, and 4-6 of the 9 primary amino groups of the lysine residues were modified. The catalytic activity and stability were investigated in a p-nitrophenyl palmitate hydrolysis reaction. After modification, CALB was activated and achieved a high catalytic efficiency in the aqueous phase (e.g., [HOOCMMIm][Cl] modification showed a 1.5-fold increase in the catalytic efficiency). The thermostability and organic solvent tolerance were significantly increased with the ILs modification (e.g., [HOOCBMIm][Cl] owned kosmotropic cation and chaotropic anion modification showed a 7-fold thermostability increase at 70 °C, 1-fold increase in 50% aqueous dimethylformamide and 5-fold increase in 50% aqueous methanol). Conformation changes were confirmed by fluorescence spectroscopy, circular dichroism spectroscopy and attenuated total reflection Fourier transform infrared spectroscopy.
State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, Nanjing University of Technology, Nanjing 210009, China. biotech@njut.edu.cn huyi@njut.edu.cn.
Ru
R
Jia
Yi
Y
Hu
Luo
L
Liu
Ling
L
Jiang
He
H
Huang
D005656:Fungal Proteins / Q000737:chemistry / Q000378:metabolism*; D007093:Imidazoles / Q000737:chemistry*; D052578:Ionic Liquids / Q000737:chemistry*; D008049:Lipase / Q000737:chemistry / Q000378:metabolism*; D015394:Molecular Structure; D055550:Protein Stability
D005656:Fungal Proteins; D007093:Imidazoles; D052578:Ionic Liquids; D008049:Lipase; C431349:lipase B, Candida antarctica