The ability of the mitochondria and the submitochondrial particles to generate a membrane potential on addition of non-penetrating electron donors and acceptors and trimethylhydroquinone is used to define more closely the organization of the electron transport chain. Ferri- and ferrocyanide added to the mitochondria are capable of causing the generation of m.p., only by exchanging the electrons with cytochrome c or Cl. Ferricyanide added to the s.m.p. produces a membrane potential by removing the electrons at three sites: from NAD·H dehydrogenase, succinic dehydrogenase but in the presence of antimycin also in the region of cytochrome b. The difference of the two sides of the mitochondrial membrane agrees with the
chemi-electrical hypothesis that the protons from the intramitochondrial water are drawn into the inlet H⁺ channels following the electrons. Therefore, the electrons move close to the inner surface of the membrane and may pass from the respiratory chain to the water-soluble acceptors. In the outlet channels protons move under the action of the intramembrane electrostatic field and to the side of the growing polarizabiIity of the medium. The protons are released into the outlet channel when the electrons are transmitted to the following carrier in the hydrophobic part of the membrane far from the outer surface of the membrane and cannot be transmitted to the water-soluble acceptors.

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