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Not to be confused with the Bohr Equation The Bohr effect is a physiological phenomenon first described in 1904 by the Danish physiologist Christian Bohr, stating that ''hemoglobin's oxygen binding affinity (see Oxygen–haemoglobin dissociation curve) is inversely related both to acidity and to the concentration of carbon dioxide.'' ''Id est'', an increase in blood CO2 concentration which leads to a decrease in blood pH will result in hemoglobin proteins releasing their load of oxygen. Conversely, a decrease in carbon dioxide provokes an increase in pH, which results in hemoglobin picking up more oxygen. Since carbon dioxide reacts with water to form carbonic acid, an increase in CO2 results in a decrease in blood pH. ==Mechanism== In deoxyhemoglobin, the N-terminal amino groups of the α-subunits and the C-terminal histidine of the β-subunits participate in ion pairs. The formation of ion pairs causes them to decrease in acidity. Thus, deoxyhemoglobin binds one proton (H+) for every two O2 released. In oxyhemoglobin, these ion pairings are absent and these groups increase in acidity. Consequentially, a proton is released for every two O2 bound. Specifically, this reciprocal coupling of protons and oxygen is the Bohr effect. Additionally, carbon dioxide reacts with the N-terminal amino groups of α-subunits to form carbamates: :R−NH2 + CO2 R−NH−COO− + H+ Deoxyhemoglobin binds to CO2 more readily to form a carbamate than oxyhemoglobin. When CO2 concentration is high (as in the capillaries), the protons released by carbamate formation further promotes oxygen release. Although the difference in CO2 binding between the oxy and deoxy states of hemoglobin accounts for only 5% of the total blood CO2, it is responsible for half of the CO2 transported by blood. This is because 10% of the total blood CO2 is lost through the lungs in each circulatory cycle.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Bohr effect」の詳細全文を読む スポンサード リンク
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