3.8. Effect of ionic liquids on the enzyme activity
Ionic liquids (ILs) is with industrially attractive advantages for
biocatalysis due to their tunable chemical properties. Several ionic
liquids ([EMIM]BF4, [BMIM]Cl,
[BMIM]BF4) were selected and added into the reaction
system with final concentration as 5 mM (Fig. S4). The activity of DA11
in [BMIM]BF4 ionic liquid was 97.8%, while
[EMIM]BF4 and [BMIM]Cl reduced the relative
enzyme activity of DA11. It is reported that
[BMIM]+ cations can strip off essential water
molecules from the enzyme surface, which cause the decreased enzyme
activity [33]. Ionic liquids also can affect enzyme activity through
direct interaction with the enzyme and by altering the microenvironment
of enzyme. Due to the conductivity and hydrophobicity, ILs are widely
applied for electrode modification to obtain high heterogeneous electron
transfer rates [34]. Therefore, ILs tolerant DA11 is promising for
its application in biosensor.