2,3-Diphosphoglycerate

Overview
  • 2,3-Diphosphoglycerate (2,3-DPG) is a special intermediate of glycolysis in erythrocytes which is rapidly consumed under conditions of normal oxygen tension. However, when hypoxia is encountered in peripheral tissues, the concentration of 2,3-DPG can accumulate to significant levels within hours. At these concentrations, 2,3-DPG can bind to hemoglobin and reduce its affinity for oxygen, resulting in a right-ward shift of the Oxygen-Hemoglobin Dissociation Curve discussed in Oxygen Transport. This results in enhanced unloading of oxygen by hemoglobin and thus results in enhanced oxygen transport to tissues encountering long-term hypoxia.
Modulation of the Oxygen-Hemoglobin Dissociation Curve
A variety of environmental factors can shift the Oxygen-Hemoglobin Dissociation Curve. Effects which are associated with increased peripheral tissue metabolism, such as reduced pH, increased CO2, increased temperature, shift the curve to the right, reducing hemoglobinâ€s affinity for oxygen and thus improving oxygen unloading. Chronic hypoxia increases the bloodâ€s concentration of 2,3-DPG which also shifts the curve to the right. The presence of HbF and carbon monoxide (CO) shift the curve to the left, increasing the oxygen affinity of hemoglobin.