Oxygen transport by haemoglobin. A comparison of whole blood, washed erythrocytes and haemoglobin solution.

The properties of haemoglobin oxygen transport were compared under three different conditions: red cell in its natural medium, i.e. plasma (whole blood), washed red cell and haemoglobin A, the former suspended, the latter solved in an iso-osmotic tris buffer. The oxygen haemoglobin affinity (expressed as P50) and the respiratory Bohr effect variations were studied with modified media and unchanged pH and 2,3-diphosphoglycerate (2,3-DPG) concentration. Provided they are refered to intra-erythrocytic pH, none of these values were changed when varying environment. These results suggest that the three major ligands (H+ ions, 2,3-DPG and CO2) interaction with haemoglobin is largely predominant upon other factors which would interfere, and can completely account for oxygen transport by haemoglobin.