The effect of erythrocyte membrane on the birefringence formation of sickle cell hemoglobin.

The birefringence formation of sickle cell hemoglobin (HbS) in a thin liquid layer was observed while its environment was deoxygenated at different rates, and the effect of membrane was examined. Under slow rate of deoxygenation at 37 degrees C, at pH 7.4, the birefringence of purified HbS appeared at a concentration higher than 24% and its relative magnitude increased as the concentration was increased. Similarly, the partial pressure of oxygen, at which the birefringence formation was evident, increased from 0 to 27 torr as the concentration of HbS was increased from 24 to 28%, but it remained the same above this protein concentration. In all the samples tested relative birefringence was largest at the slow rate of deoxygenation (30 torrO2/min) and the magnitude decreased as the rate of deoxygenation was increased. The samples showed different sensitivity to the rate of deoxygenation. For example, while the total untreated hemolysate made by freeze-thawing of packed sickle cells was most resistant to the increased rates of deoxygenation, purified HbS was not. Washed open ghosts partially restored the birefringence formation pattern of purified HbS. The results indicate that the inner surface of the membranes of erythrocytes could behave as a template for large HbS polymer formation at relatively higher rates of deoxygenation.