Fluctuation driven transport and models of molecular motors and pumps

R. Dean Astumian, Imre Derényi

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Non-equilibrium fluctuations can drive vectorial transport along an anisotropic structure in an isothermal medium by biasing the effect of thermal noise (k(B)T). Mechanisms based on this principle are often called Brownian ratchets and have been invoked as a possible explanation for the operation of biomolecular motors and pumps. We discuss the thermodynamics and kinetics for the operation of microscopic ratchet motors under conditions relevant to biology, showing how energy provided by external fluctuations or a non-equilibrium chemical reaction can cause unidirectional motion or uphill pumping of a substance. Our analysis suggests that molecular pumps such as Na,K-ATPase and molecular motors such as kinesin and myosin may share a common underlying mechanism.

Original languageEnglish
Pages (from-to)474-489
Number of pages16
JournalEuropean Biophysics Journal
Issue number5
Publication statusPublished - Sep 17 1998



  • Free energy transduction
  • Ion pumps
  • Maxwells demon
  • Molecular motors
  • Ratchets

ASJC Scopus subject areas

  • Biophysics

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