title: Influence of ethylenediaminetetraacetic acid (EDTA) on the structural stability of endoglucanase from Aspergillus aculeatus.
abstract: 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 K(m) values for control and in the presence of EDTA are 0.060 and 0.044%, respectively, and K(cat) was 1.9 min(-1) in the presence of EDTA. The kinetic parameters indicated a decrease in the K(m) with an increase in the K(cat). 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 T(m) 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 K(cat) and flexible conformation of the enzyme. The stability of endoglucanase increased in the presence of EDTA.
authors.affiliation: Department of Protein Chemistry and Technology, Central Food Technological Research Institute, Mysore 570 020, India.
authors.forename: Gajendra S
authors.initials: GS
authors.lastname: Naika
authors.forename: Purnima Kaul
authors.initials: PK
authors.lastname: Tiku
mesh_terms: D001230:Aspergillus / Q000201:enzymology*; D002480:Cellulase / Q000737:chemistry* / Q000187:drug effects / Q000378:metabolism*; D002614:Chelating Agents / Q000494:pharmacology*; D004492:Edetic Acid / Q000494:pharmacology*; D004795:Enzyme Stability / Q000187:drug effects; D006358:Hot Temperature; D011487:Protein Conformation / Q000187:drug effects; D013050:Spectrometry, Fluorescence
chemical_list: D002614:Chelating Agents; D004492:Edetic Acid; D002480:Cellulase