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Differential scanning calorimetric studies of a Bacillus halodurans alpha-amylase

Hashim, Suhaila LU ; Hatti-Kaul, Rajni LU ; Andersson, Maria LU ; Mulaa, F J and Mattiasson, Bo LU (2005) In Biochimica et Biophysica Acta. General Subjects 1723(1-3). p.184-191
Abstract
The thermal unfolding of Amy 34, a recombinant alpha-amylase from Bacillus halodurans, has been investigated using differential scanning calorimetry (DSC). The denaturation of Amy 34 involves irreversible processes with an apparent denaturation temperature (T-m) of 70.8 degrees C at PH 9.0, with four transitions, as determined using multiple Gaussian curves. The T-m increased by 5 degrees C in the presence of 100-fold molar excess of CaCl2 while the aggregation of Amy 34 was observed in the presence of 1000-fold molar excess of CaCl2. Increase in the calcium ion concentration from 1 - to 5-fold molar excess resulted in an increase in calorimetric enthalpy (Delta H-cal), however, at higher concentrations of CaCl2 (up to 100-fold), Delta... (More)
The thermal unfolding of Amy 34, a recombinant alpha-amylase from Bacillus halodurans, has been investigated using differential scanning calorimetry (DSC). The denaturation of Amy 34 involves irreversible processes with an apparent denaturation temperature (T-m) of 70.8 degrees C at PH 9.0, with four transitions, as determined using multiple Gaussian curves. The T-m increased by 5 degrees C in the presence of 100-fold molar excess of CaCl2 while the aggregation of Amy 34 was observed in the presence of 1000-fold molar excess of CaCl2. Increase in the calcium ion concentration from 1 - to 5-fold molar excess resulted in an increase in calorimetric enthalpy (Delta H-cal), however, at higher concentrations of CaCl2 (up to 100-fold), Delta H-cal was found to decrease, accompanied by a decrease in entropy change (Delta S), while the T., steadily increased. The presence of 100-fold excess of metal chelator, EDTA, resulted in a decrease in T-m by 10.4 degrees C. T-m was also decreased to 61.1 degrees C and 65.9 degrees C at PH 6.0 and PH 11.0, respectively. (c) 2005 Elsevier B.V. All rights reserved. (Less)
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author
organization
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Contribution to journal
publication status
published
subject
in
Biochimica et Biophysica Acta. General Subjects
volume
1723
issue
1-3
pages
184 - 191
publisher
Elsevier
external identifiers
  • wos:000229691900021
  • pmid:15826839
  • scopus:19744371497
ISSN
0304-4165
DOI
10.1016/j.bbagen.2005.03.004
language
English
LU publication?
yes
id
26b85e4c-547c-479c-a260-879fa74985c7 (old id 155153)
date added to LUP
2007-07-02 11:26:17
date last changed
2017-01-01 07:21:15
@article{26b85e4c-547c-479c-a260-879fa74985c7,
  abstract     = {The thermal unfolding of Amy 34, a recombinant alpha-amylase from Bacillus halodurans, has been investigated using differential scanning calorimetry (DSC). The denaturation of Amy 34 involves irreversible processes with an apparent denaturation temperature (T-m) of 70.8 degrees C at PH 9.0, with four transitions, as determined using multiple Gaussian curves. The T-m increased by 5 degrees C in the presence of 100-fold molar excess of CaCl2 while the aggregation of Amy 34 was observed in the presence of 1000-fold molar excess of CaCl2. Increase in the calcium ion concentration from 1 - to 5-fold molar excess resulted in an increase in calorimetric enthalpy (Delta H-cal), however, at higher concentrations of CaCl2 (up to 100-fold), Delta H-cal was found to decrease, accompanied by a decrease in entropy change (Delta S), while the T., steadily increased. The presence of 100-fold excess of metal chelator, EDTA, resulted in a decrease in T-m by 10.4 degrees C. T-m was also decreased to 61.1 degrees C and 65.9 degrees C at PH 6.0 and PH 11.0, respectively. (c) 2005 Elsevier B.V. All rights reserved.},
  author       = {Hashim, Suhaila and Hatti-Kaul, Rajni and Andersson, Maria and Mulaa, F J and Mattiasson, Bo},
  issn         = {0304-4165},
  language     = {eng},
  number       = {1-3},
  pages        = {184--191},
  publisher    = {Elsevier},
  series       = {Biochimica et Biophysica Acta. General Subjects},
  title        = {Differential scanning calorimetric studies of a Bacillus halodurans alpha-amylase},
  url          = {http://dx.doi.org/10.1016/j.bbagen.2005.03.004},
  volume       = {1723},
  year         = {2005},
}