Kinetic study of the inhibition of ionic liquids on the trypsin activity

The kinetics of the inhibitory effects of ionic liquids (ILs) on the trypsin activity was useful for the practical applications, herein, kinetic information of the IL-trypsin interaction was systematically studied by infrared (IR) and ultraviolet-visible (UV–Vis) spectroscopies. Experimental results indicate that the presence of ILs makes the Michaelis constant ( K m ) of the enzyme reaction increase, meanwhile, the maximum rate ( V max ) keeps constant, suggesting that the inhibition of ILs on the trypsin activity belongs to the reversible-competitive type. IR and UV–Vis spectra show that the presence of ILs does not change the secondary structures of trypsin. After removing the ILs, the trypsin activity can be recovered; the activation energy keeps constant without and with the presence of ILs.