Interaction of a surface-active base with the fraction of membrane-bound Williams’ protons

According to the Williams model, the work of mitochondrial respiratory H+ pumps gives rise to a fraction of membrane-bound protons (R-protons) that have excess free energy, which is used in the reaction of ATP synthesis. We have earlier managed to detect such a fraction in mitochondria and mitoplasts and to rigorously show (for mitoplasts) that the non-equilibrium R-proton fraction is localized on the surface of the inner membrane. Here we show that a surface-active compound 2,4,6-trichloro-3-pentadecylphenol anion (TCP-C15) selectively interacts with the R-proton fraction, and describe in detail its influence on mitochondrial respiration under conditions of R-proton generation. We also report endogenous regulation of the R-proton fraction volume, which is performed by the phosphate transport system. The results are discussed in terms of the local coupling model.