Effect of Metal Ions and EGTA on the Optical Properties of Concanavalin A at Alkaline pH
Abstract:In our earlier communications, we reported the effect of salts and alcohols on a-chymotrypsinogen  and the existence of stable intermediates at low pH in bromelain  and glucose oxidase . In the present study, the role of metal ions and EGTA on the conformation of concanavalin A at alkaline pH was studied by near- and far-UV circular dichroism, fluorescence emission spectroscopy and binding of a hydrophobic dye, 1-anilino-8-naphthalene sulfonate (ANS). Far-UV CD spectra showed the transition from an ordered secondary structure at pH 7 with a trough at 223 nm to a relatively unordered state at pH 12. Near-UV CD spectra showed the loss of signal at 290 nm, thereby indicating the disruption of native three dimensional structure. Maximum ANS binding occurred at pH 12 suggesting the presence of an intermediate or molten globule-like state at alkaline pH.
Document Type: Review Article
Affiliations: Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh-202002, India.
Publication date: February 1, 2005
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