Influence of Ethylenediaminetetraacetic Acid (EDTA) on the Structural Stability of Endoglucanase from Aspergillus aculeatus

The effect of the chelating agent ethylenediaminetetraacetic acid (EDTA) on the structure and function of
endoglucanase is studied. In the presence of 2 mM EDTA, endoglucanase showed an enhanced enzymatic activity of 1.5-fold
compared to control. No further change in activity was observed with increase in the concentration of EDTA to 5 mM. The Km
values for control and in the presence of EDTA are 0.060 and 0.044%, respectively, and Kcat was 1.9 min�1 in the presence of EDTA.
The kinetic parameters indicated a decrease in the Km with an increase in the Kcat. Far-ultraviolet circular dichroism (far-UV-CD)
results showed a 20% decrease in ellipticity values at 217 nm in the presence of EDTA compared to native enzyme. The apparent Tm
shifted from a control value of 57(1 to 76(1 �C in the presence of EDTA (5 mM). The above results suggested that the enhanced
activity in the presence of EDTA is due to an increase in the Kcat and flexible conformation of the enzyme. The stability of
endoglucanase increased in the presence of EDTA.