The effects of deoxygenation of adult and fetal hemoglobin on the synthesis of red cell 2,3-diphosphoglycerate and its in vivo consequences

Abstract

Patients over 1 month of age with arterial oxygen pressures of less than 60 mm Hg were found to have elevated red cell 2,3-diphosphoglycerate (2,3-DPG) levels and blood with a decreased affinity for oxygen. The increase in 2,3-DPG was proportional to the degree of hypoxemia. In patients under 1 month of age this relationship was not observed. Red cells from adults, but not newborns, showed rapid increases in 2,3-DPG when incubated under nitrogen. Adult, but not fetal, deoxyhemoglobin was shown to facilitate in vitro synthesis of 2,3-DPG by binding this organic phosphate and relieving the product inhibition of 2,3-DPG mutase. Throughout a wide range change in oxygen affinity as measured by the P₅₀ is linear with respect to the 2,3-DPG concentration; a change of 430 mμmoles of 2,3-DPG/ml of red blood corpuscles (RBC) resulting in a change of the P₅₀ of 1 mm Hg. It appears that the 2,3-DPG of the adult's red cells responds rapidly to metabolic and environmental influences and in turn effects metabolism and the cellular environment. Many of these effects are not shared by the red cells of the newborn.