The mechanism of entry of protons into erythrocyte membrane surroundings in the 8-th stage of the 9 staged closed cycle of proton conductance is needed the more detailed explanation, because cell membranes are generally impermeable to charged ions (i.e. H+, HCO3−). But should be say that during many years evolution development of organism had been formed the more appropriate way to regulate this difficulty by using the mechanism, named as exchange bicarbonate for chloride using the anion exchanger protein Band 3. During these processes have been conducted the following biological events, which may be named as "the reappearance of free protons" and may be described this pathway as “at first :the release of protons from food molecules, at second :the formation of proton gradients-ATP synthesis, heat energy formation, at third :the protonation of oxygen with formation of metabolic water within mitochondrial matrix, at fourth: the exit of ATP, carbon dioxide and metabolic water from mitochondria, at fifth :the formation of carbonic acid from metabolic water and carbon dioxide and formation of free protons and bicabonate from carbonic acid in cytosols of all cells, plasma, at sixth: entry of bicarbonate to erythrocyte membrane surroundings ,bearing protons formed from food molecules in electron transport complexes according to principle as reutilizing of carbon dioxide to mechanism of entry of protons within the 9 staged closed cycle of proton conductance (M.Ambaga, A.Tumen-Ulzii, 2016). The basic parameters of 8-th stage of the 9 staged closed cycle of proton conductance are metabolic water, carbon dioxide, free protons and bicarbonate. Meanwhile, metabolic water and carbon dioxide have been generated in the mitochondrial matrix and the formation of free protons (reappearance of free protons) and bicarbonate (protonated oxygen) have been conducted in cytosols of all cells, plasma and erythrocyte membrane surroundings. In conducting of process of entry of protons into erythrocyte membrane surroundings within 8-th stage of the 9 staged closed cycle of proton conductance more important role is played the Protein-Band 3. Protein- Band 3 is present in the basolateral face of the various cells, including the red cells, they generate hydrogen ions and bicarbonate ions from carbon dioxide and water - a reaction catalysed by carbonic anhydrase. This is crucial for CO2 uptake by erythrocyte membrane surroundings and conversion (by hydration catalysed by carbonic anhydrase) into a proton and a bicarbonate ion. Also, in conducting of process of entry of protons into erythrocyte membrane surroundings within 8-th stage of the 9 staged closed cycle of proton conductance more important role is played the Chloride shift (also known as the Hamburger shift or lineas phenomenon, named after Hartog Jakob Hamburger) during which occurs the exchange of bicarbonate (bearing protons, generated in mitochondrial matrix) and chloride (Cl−) across the membrane of red blood cells. In such way, more interesting processes have been occurred in 8-th stage of proton conductance, which conditioned the following expiration of carbon dioxide and also release of oxygen from hemoglobin molecules and delivery of oxygens to all cells in the result of entry of protons into erythrocyte membrane surroundings owing to existing of 8-th stage of the 9 staged closed cycle of proton conductance.
