Stability and kinetics of a bifunctional amylase/trypsin inhibitor

Alagiri, Srinivasan ; Singh, Tej P. (1993) Stability and kinetics of a bifunctional amylase/trypsin inhibitor Biochimica et Biophysica Acta (BBA) - Protein Structure and Molecular Enzymology, 1203 (1). pp. 77-84. ISSN 0167-4838

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The stability of the bifunctional amylase/trypsin inhibitor from ragi (Indian finger millet, Eleusine coracana) has been studied y methods of circular dichroism, UV absorption and intrinsic fluorescence. The inhibitor is stable in 8 M urea and 6 M guanidine-HCl. In 150 mM NaCl, thermal denaturation does not occur up to 90°C. However, it is irreversibly denatured in 5 mM NaCl if heated over 73°C. The acidic denaturation is reversible in both high and low salt conditions, but it shows different behavior below pH 1.65 under similar salt conditions. The helical content is about 2-4% in the pH range of 7-9 at which the inhibitor is active maximally. The NaCl concentration does not have a significant effect on the secondary strucure elements. The β-strand form does not show much variation under various conditions. Arg34-Leu35 is the reactive peptide bond in the trypsin-binding site. Trp and Tyr are involved in the binding with amylase. The bifunctional inhibitor represents the sum o individual inhibitors of trypsin and amylase.

Item Type:Article
Source:Copyright of this article belongs to Elsevier Science.
Keywords:Bifunctional Inhibitor; Amylase/Trypsin Inhibitor; Protein Denaturation; Inhibition Kinetics; (E. coracana)
ID Code:49086
Deposited On:18 Jul 2011 13:35
Last Modified:18 Jul 2011 13:35

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