Mechanism of long-range proton translocation along biological membranes

► Long-range lateral proton translocation is due to accompanying bulk diffusion. ► Protons diffuse alternatively along surface and in bulk. ► Protons desorb and re-adsorb at surface many times before equilibrating with bulk. ► Surface depletion is compensated by return of the released protons. ► Surface protons decay very slowly, allowing for local coupling.