The final product of cellular respiration is the proton motive force, formed by protons pumped out of the membrane and by the voltage due to all charges. While Mitchell’s original theory considered pumped protons released immediately to the bulk external medium, that has been criticized. Today there is a good amount of research showing that protons tend to remain confined in 2D in proximity with the membrane (one review can be found here). This would explain how certain extremophiles can survive in very basic niches (poor in protons), where the proton motive force, defined from the bulk pH, cannot sustain ATP synthesis.

As far as I have been able to discover, the existence of such “surface protons” has only been shown in vitro (e.g. in a sustained lipid bilayer).

Is there any experimental evidence of such “surface protons” in intact cells, i.e. in vivo?

  • $\begingroup$ I have take the liberty to edit question (you can always revert it if you disagree) to give it more focus. I particularly dislike questions asking for the "consensus in the field", and this is not necessary — all that will serve is evidence, and that is assumed to include citations. Remember, at one time the consensus here was squiggle-X! In fact, this is a biophysics question, although of considerable interest, I think is likely beyond the scope of all but one or two of the members of this list. You are probably as well doing your own search for papers citing the one you mentioned. $\endgroup$
    – David
    Mar 21 at 18:54


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