کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9573264 | 1388894 | 2005 | 12 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Effect of polyol osmolytes on ÎGD, the Gibbs energy of stabilisation of proteins at different pH values
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
پیش نمایش صفحه اول مقاله
![عکس صفحه اول مقاله: Effect of polyol osmolytes on ÎGD, the Gibbs energy of stabilisation of proteins at different pH values Effect of polyol osmolytes on ÎGD, the Gibbs energy of stabilisation of proteins at different pH values](/preview/png/9573264.png)
چکیده انگلیسی
Thermal denaturation curves of lysozyme and ribonuclease-A were determined by measuring their far-UV circular dichroism (CD) spectra in the presence of different concentrations of five polyols (sorbitol, glycerol, mannitol, xylitol and adonitol) at various pH values in the range 7.0-1.9. The denaturation curve at each polyol concentration and pH was analysed to obtain values of Tm (midpoint of denaturation) and ÎHm (enthalpy change at Tm), and these ÎHm and Tm values obtained at different pH values were used to obtain ÎCp (constant-pressure heat capacity change) at each polyol concentration. Using values of ÎHm, Tm and ÎCp in the Gibbs-Helmholtz equation, ÎGD° (Gibbs energy change at 25 °C) was determined at a given pH and polyol concentration. Main conclusions of this study are that polyols have no significant effect on ÎGD° at pH 7.0, and they stabilise proteins in terms of ÎGD° against heat denaturation at lower pH values. Other conclusions of this study are: (i) Tm at each pH increases with increasing polyol concentration, (ii) ÎHm remains, within experimental error, unperturbed in the presence of polyols, and (iii) ÎCp depends on polyol concentration. Furthermore, measurements of the far- and near-UV CD spectra suggested that secondary and tertiary structures of both proteins in their native and denatured states are not perturbed on the addition of polyols.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Biophysical Chemistry - Volume 117, Issue 1, 22 August 2005, Pages 1-12
Journal: Biophysical Chemistry - Volume 117, Issue 1, 22 August 2005, Pages 1-12
نویسندگان
Inamul Haque, Rajendrakumar Singh, Ali Akbar Moosavi-Movahedi, Faizan Ahmad,