Temperature dependence of internal friction in enzyme reactions

Anna Á Rauscher, Zoltán Simon, Gergely J. Szöllosi, László Gráf, Imre Derényi, Andras Malnasi-Csizmadia

Research output: Contribution to journalArticle

11 Citations (Scopus)


Our aim was to elucidate the physical background of internal friction of enzyme reactions by investigating the temperature dependence of internal viscosity. By rapid transient kinetic methods, we directly measured the rate constant of trypsin 4 activation, which is an interdomain conformational rearrangement, as a function of temperature and solvent viscosity. We found that the apparent internal viscosity shows an Arrhenius-like temperature dependence, which can be characterized by the activation energy of internal friction. Glycine and alanine mutations were introduced at a single position of the hinge of the interdomain region to evaluate how the flexibility of the hinge affects internal friction. We found that the apparent activation energies of the conformational change and the internal friction are interconvertible parameters depending on the protein flexibility. The more flexible a protein was, the greater proportion of the total activation energy of the reaction was observed as the apparent activation energy of internal friction. Based on the coupling of the internal and external movements of the protein during its conformational change, we constructed a model that quantitatively relates activation energy, internal friction, and protein flexibility.

Original languageEnglish
Pages (from-to)2804-2813
Number of pages10
JournalFASEB Journal
Issue number8
Publication statusPublished - Aug 1 2011


  • Kramers' theory
  • Rough energy landscape
  • Trypsin activation

ASJC Scopus subject areas

  • Biotechnology
  • Biochemistry
  • Molecular Biology
  • Genetics

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