Hypotheses on the Mechanism of Electron Motion in Biological Membranes

Hypotheses on the Mechanism of Electron Motion in Biological Membranes 

The electron in the electron transport chain is not free like in a metal wire. Therefore the electron motion in each act involves surmounting an energy barrier. As was shown in Refs. 16 and 108-110, a substantial role in this process is played by the conformations of the macromolecular components of the electron transport chain. Nevertheless, the simplest model systems of electron transport realized on bilayer lipid membranes were virtually based on the concept of a membrane as a thin liquid hydrocarbon in which a substance capable of redox transformations is dissolved, the products of this reaction being able to diffuse inside the bilayer. The electron transport from the aqueous phase containing a reducer amounts to injection of charges into the nonaqueous phase if it contains an electron acceptor  

At the same time, on the other side of the membrane, if there occurs a transmembrane charge transfer, the reduced form mD 

Consequently, the electron transport across the membrane proves possible if there exists a redox pair dissolved in the membrane which acts as a charge carrier  

When bilayers are used, and specifically when their photoproperties are investigated, investigators often resort to the tunnel mechanism of electron transport through the bilayer. That is equivalent to assuming that the membrane is approximated as a thin insulator or semiconductor film. A charge injected in the membrane is localized either on the molecules which make up the membrane or on the additions having a greater affinity for the electron than the molecules of which the membrane is made up  

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