In this review, we discuss the mechanisms of generation of membrane-bound protons using different energy sources in model and natural systems. Analysis of these mechanisms revealed that all three types of reactions include the same principal stage, which is dissociation of electrically neutral Brønsted acids at the interface during transition from the hydrophobic phase to water with a low dielectric constant. Special attention is paid to the fact that in one of the analyzed model systems, membrane-bound protons provide energy for the reaction of ATP synthesis. Similar mechanism for the generation of membrane-bound protons has been found in natural membranes involved in oxidative phosphorylation, in particular, on the membranes of mitoplasts and mitochondria. The energy of oxidative reactions required for ATP synthesis, is stored at the intermediate stage not only in the form of transmembrane electrochemical potential of protons, but also and perhaps mostly, as protons attached to the inner mitochondrial membrane. The process of energy storage in mitochondria is linked to the transfer of protons that simultaneously perform two functions. Protons on the membrane surface carry free energy and, at the same time, act as substrates facilitating the movement of F1F0-ATP-synthase biological machine.
Keywords: hydrogen ion; membrane; membrane bound proton; mitochondria; oxidative phosphorylation; supercapacitor.