Enthalpy/entropy compensation phenomena in the reduction thermodynamics of electron transport metalloproteins

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• 作者：Gianantonio Battistuzzi ; Marco Borsari ; Giulia Rocco ; Antonio Ranieri and Marco Sola
• 关键词：Electron transport ; Enthalpy ; Entropy ; Metalloproteins ; Thermodynamics
• 刊名：Journal of Biological Inorganic Chemistry
• 出版年：2004
• 出版时间：January 2004
• 年：2004
• 卷：9
• 期：1
• 页码：23-26
• 全文大小：242 KB
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Life Sciences
  Biochemistry
  Microbiology
  
• 出版者：Springer Berlin / Heidelberg
• ISSN：1432-1327

文摘

Compensation phenomena between the enthalpy and entropy changes of the reduction reaction for all classes of electron transport metalloproteins, namely cytochromes, iron-sulfur, and blue copper proteins, are brought to light. This is the first comprehensive report on such effects for biological redox reactions. Following Grunwalds approach for the interpretation of H/S compensation for solution reactions, it is concluded that reduction-induced solvent reorganization effects involving the hydration shell of the molecule dominate the reduction thermodynamics in these species, although they have no net effect on the E° values, owing to exact compensation. Thus the reduction potentials of these species are primarily determined by the selective enthalpic stabilization of one of the two oxidation states due to ligand binding interactions and electrostatics at the metal site and by the entropic effects of reduction-induced changes in protein flexibility.