engleski

The chemical cycle kinetics close to the equilibrium state and electrical circuit analogy

A free-energy transducing macromolecule, interacting with ligands, and cycling through discrete states, can be described by Hill's diagram. Close to equilibrium, where linear flux-force relationships hold, we develop a method of the construction of the electrical circuit corresponding to Hill's diagram. The method of contour fluxes is used to form a general linear theory. Thevenin's theorem is used to find the efficiency of free-energy transduction. Maximal power transfer conditions are then found, too. A much more elegant proof of Jeans's 1923 theorem is then derived. We show that this theorem is equivalent to maximum entropy production principle for steady state linear electrical circuits. It follows that fluxes in the corresponding steady state enzymatic cycle kinetics(in the linear range for fixed ligand concentrations) distribute themselves so as to make the entropy production maximal. Prigogine's minimum entropy production theorem refers to the very special steady state and is much more restricted in its application than the maximum entropy production theorem.

free-energy transduction; Thevenin's theorem; Jeans's theorem; entropy production; enzyme-ligand complex

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