During ETD, the protons driving cleavage remain localized to basic residues and cannot extend into the nonpolar TMDs.
Surprisingly, the protons driving CAD cleavage are not just delocalized but in fact mobilized farther away from basic residues than would be predicted by a random model.
ETD is simply too localized to basic residues to cleave in TMDs, while the protons driving CAD and HCD are pushed there due to repulsion from those same basic residues.
The uncoupler FCCP disrupts the mitochondrial proton gradient driving ATP production, giving a measurement of maximal respiratory capacity.
Fluorescence measurement of intracellular pH showed no reduction in the proton gradient driving PepT1-mediated apical uptake.
To determine whether the proton-driving force for peptide uptake had been affected by AICAR treatment, the pHi of Caco-2 cells grown on cover slips was measured by fluorimetry using the pH-sensitive dye BCECF.
Under salinity, the up-regulation of the vacuolar H+-ATPase genes (VHA), SsVHA-H and SsVHA-B and the increase in the activity of V-H+-ATPase provide the proton-driving force for sequestering Na+ in leaf vacuoles of Suaeda salsa (Li et al. 2004, 2006).
These values of ΔpH are consistent with a point of view that under steady-state conditions the proton gradient ΔpH is the main contributor to the proton motive force driving the operation of ATP synthesis, provided that stoichiometric ratio H+/ATP is n ≥ 4 4.7.
