Acta Chimica Sinica ›› 2003, Vol. 61 ›› Issue (12): 1949-1954. Previous Articles     Next Articles

Original Articles

等温滴定量热法和荧光滴定法研究十二烷基硫酸钠与纤维素酶的结合

项瑾;梁毅;陈楠   

  1. 武汉大学生命科学学院
  • 出版日期:2003-12-15 发布日期:2003-12-15

Studies on the Binding of Sodium Dodecyl Sulfate to Cellulase by Isothermal Titration Calorimetry and Fluorescence Titration

Xiang Jin;Liang Yi;Chen Nan   

  1. College of Life Sciences, Wuhan University
  • Online:2003-12-15 Published:2003-12-15

Thermodynamics of the interaction of an anionic detergent, sodium dodecyl sulfate (SDS), with cellulase from Trichoderma reesei has been studied by isothermal titration calorimetry and fluorescence titration. The binding of SDS to cellulase is driven by a favorable entropy increase with a less favorable enthalpy decrease, and shows strong enthalpy-entropy compensation and weak affinity. A larger negative heat capacity change of the binding, - 186 J·mol~(-1)·K~(-1), at all temperatures examined indicates that hydrophobic interaction is a major force for the binding. SDS quenches the intrinsic fluorescence of cellulase, and causes both a red shift in the maximum fluorescence emission wavelength of the protein and a partial loss in the enzymatic activity. These results indicate that the interaction of SDS with cellulase includes contributions of the binding and the partial unfolding of die protein induced by SDS.

Key words: CALORIMETRY, FLUORIMETRIC ANALYSIS, CELLULASE, SDS, FLUORESCENCE QUENCHER

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