This title appears in the Scientific Report :
2011
Please use the identifier:
http://dx.doi.org/10.2174/092986611794578305 in citations.
Structural stability of soybean (Glycine max) a-amylase: Properties of the unfolding transition studied with fluorescence and CD spectroscopy
Structural stability of soybean (Glycine max) a-amylase: Properties of the unfolding transition studied with fluorescence and CD spectroscopy
Stability and unfolding of mammalian and microbial alpha-amylases have been intensively investigated. However, there is only limited information available on the structural stability of plant alpha-amylases, namely of the two isoenzymes from barley AMY1 and AMY2, of the alpha-amylase from mung bean...
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Personal Name(s): | Kumari, A. |
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Rosenkranz, T. / Kayastha, A.M. / Fitter, J. | |
Contributing Institute: |
Molekulare Biophysik; ICS-5 |
Published in: | Protein and peptide letters, 18 (2011) S. 253 - 260 |
Imprint: |
Schiphol
Bentham Science Publ.
2011
|
Physical Description: |
253 - 260 |
DOI: |
10.2174/092986611794578305 |
Document Type: |
Journal Article |
Research Program: |
BioSoft: Makromolekulare Systeme und biologische Informationsverarbeitung |
Series Title: |
Protein and Peptide Letters
18 |
Subject (ZB): | |
Publikationsportal JuSER |
Stability and unfolding of mammalian and microbial alpha-amylases have been intensively investigated. However, there is only limited information available on the structural stability of plant alpha-amylases, namely of the two isoenzymes from barley AMY1 and AMY2, of the alpha-amylase from mung bean (Vigna radiata), and of the alpha-amylase from malted sorghum (Sorghum bicolor). We report here the stability of soybean alpha-amylase (GMA), against elevated temperatures and chemical denaturants (GndHCl) by employing circular dichroism and fluorescence spectroscopy. Since it is well-known that calcium ions play a crucial role for enzymatic activity and stability of alpha-amylases, we performed our studies with calcium bound and calcium free GMA. The thermal unfolding transition temperature decreased from 72 degrees C for calcium saturated samples to 57 degrees C for the case of calcium depleted GMA. Similarly, the GndHCl transition concentration was lowered from 0.70 M for calcium bound GMA to 0.41 M in the absence of calcium. Thermal unfolding of GMA is irreversible due to aggregation of the unfolded state. GMA unfolded in 6 M GndHCl shows high degree of reversibility after diluting the unfolded enzyme in native buffer containing 7 M glycerol. Furthermore, the refolded enzyme showed 93% of activity. |