초록
<P><B>Abstract</B></P> <P>This study evaluated the effect of the addition of the following ionic liquids (IL): choline chloride (CC), tetramethylammonium bromide (TB) and 1‑ethyl‑3‑methylimidazolium bromide (EM), on some biochemical properties including enzymatic activity and different kinetic parameters of commercial proteases. The enzyme-IL combinations that showed the highest increases in enzyme activities were as follows: CC (0.5mM) and Neutrase® 0.8L; CC (5mM) and Flavourzyme® 500L; TB (2000mM) and Alcalase® 2.4L, with relative increases of 20, 15 and 150% in protease activities, respectively, compared to the control assays. The combination TB and Alcalase® 2.4L showed a reduction of 50% of the activation energy (E<SUB>a</SUB>), an increase of the relation V<SUB>max</SUB>/K<SUB>m</SUB> of 35% and a 16-fold rise in the values of t<SUB>1/2</SUB>, and D. Neutrase® 0.8L combined with CC showed an increase of 20% in the relation V<SUB>max</SUB>/K<SUB>m</SUB>. The combination Flavourzyme® 500L and CC presented a 20% higher value of the relation V<SUB>max</SUB>/K<SUB>m</SUB> and a 2-fold increase in the values of t<SUB>1/2</SUB> and D compared to the control assay. In summary, the most positive effects observed in this study included proteases with improved activity and stability properties and a greater affinity for the substrate.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Ionic liquids positively altered the catalytic action of commercial proteases; </LI> <LI> Increases ranging from 15% to 150% were detected in protease activities treated with ionic liquids; </LI> <LI> The half-life and decimal reduction time of theproteases were increased by up to 16-fold in the presence of ionic liquids; </LI> <LI> The kinetic parameters Km and Vmax indicated higher affinity and reaction rates for protease treated with ionic liquids. </LI> </UL> </P>