کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
217033 1426291 2010 5 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Thermodynamic study of the dimerization of 8-anilino-1-naphthalenesulfonic acid by isothermal titration calorimetry
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی مهندسی شیمی (عمومی)
پیش نمایش صفحه اول مقاله
Thermodynamic study of the dimerization of 8-anilino-1-naphthalenesulfonic acid by isothermal titration calorimetry
چکیده انگلیسی

Dimerization of the fluorescence probe, 8-anilino-1-naphthalenesulfonic acid (ANS) in aqueous media have been studied by isothermal titration calorimetry (ITC). ITC experiments carried out at different pHs show that dimerization constants are highly pH dependent, decreasing their values with increasing pH. No dimerization is detected over pH 7. Analyzing the dependence of Kdim on pH, using a model that only considers dimers between zwitterionic molecules of ANS, a value of 5.6 for the pK of anilinium moiety is obtained. It is in agreement with the pK determined spectrophotometrically. The dimerization process is enthalpically disfavored and entropically driven at all pH and temperatures studied, indicating that hydrophobic effect has an important role on the formation of dimers. Although dimerization constants are low, dimerization equilibria must be taken into account when the energetics of the interaction of ANS to a protein is studied at pH below 7.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: The Journal of Chemical Thermodynamics - Volume 42, Issue 3, March 2010, Pages 337–341
نویسندگان
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