OXYGENATION PROPERTIES AND 2, 3-DIPHOSPHOGLYCERATE OF HUMAN ADULT AND FETAL BLOOD

Oxygen dissociation curves of human adult and cord blood were constructed over a wide range of pH values (5.9-8.7). The cord blood was characterized by a high oxygen affinity as compared with adult blood in the pH region above 6.3. Below that pH region the relationship was reversed. The intracellular pH and 2, 3-diphosphoglycerate (DPG) content of red cells of these two kinds of blood were little different. Upon their incubation at 38°C, both kinds of blood showed an increase in oxygen affinity concomitant with a decrease in the DPG content. From these experiments with the two sorts of blood incubated for various lengths of time it was concluded that the higher oxygen affinity of fetal blood was due mostly to the predominant presence of hemoglobin F, which is not different in oxygen affinity from hemoglobin A but which is quite different in susceptibility to the inhibitory effect of DPG upon oxygen affinity.