The oxidation of hæmoglobin to methæmoglobin by oxygen

It has long been known that methæmoglobin is slowly formed in solutions of hæmoglobin containing dissolved oxygen but the rate of oxidation has not been measured. With the recent analytical methods of van Slyke and of Conant it is possible to determine whether the decrease in concentration of hæmoglobin is due wholly to the formation of methæmoglobin or partly, as has been suggested, to other reactions, denaturation and inactivation. The present paper describes measurements of the rate of oxidation at a constant pressure of oxygen using laked blood diluted in phosphate buffers.Material and Methods .Blood .—Fresh ox-blood was defibrinated by shaking with glass beads and laked by repeated freezing and thawing. This stock solution was kept at —20°C. and thawed when required. Centrifuging did not alter the concentration of pigment nor did removal of cell fragments by this method change the subsequent rate of oxidation.