Biochemistry: The Chemical Reactions of Living Cells, Volume 2 - D. Metzler 1980
On how electrons meet oxygen, how ATR is formed in the process, and some related phenomena
Electron transport chain and oxidative phosphorylation
Energy-dependent processes in mitochondria
Mitochondrial ATP synthesis is strongly inhibited by oligomycin. However, there are other processes that, while utilizing energy from the Electron Transport Chain, are insensitive to oligomycin. These include Ion transport across the mitochondrial membrane and another energy-dependent process—the "reversed electron flow" from succinate to NAD+ (Sec. D,7). In both cases, oligomycin has no effect, whereas dinitrophenol and other uncoupling agents block both processes. All these facts can be understood by assuming that a high-energy intermediate, X~Y, is synthesized in the presence of oligomycin, and that reversed electron flow and ion pumping can be driven by the Free energy of Hydrolysis of this intermediate without ATP formation. Dinitrophenol uncouples all reactions by causing the hydrolysis of X~Y, whereas oligomycin only affects ATP synthesis. These observations are also explained by Mitchell's hypothesis, according to which ion transport precedes ATP synthesis.
Another energy-dependent process is the transhydrogenase reaction [Equation (11-12)].
Last update: 06/08/2026
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