Rate of the Bohr shift in human red cell suspensions

Abstract

We have measured the rate at which the O2 tension rises in a partially oxygenated suspension of normal human red cells at 37 C as a result of a sudden rise in CO2 tension (the Bohr shift) in a Hartridge-Roughton rapid reaction apparatus. A Teflon covered platinum electrode was used to measure O2 tension. The rise in O2 tension had an average half time of 0.12 sec following increments of 18–65 mm Hg in CO2 tension in twelve experiments on the blood of three normal individuals. The comparable movement of O2 out of the red cell as a result of a decrease in ambient O2 tension at a constant CO2 tension had an average half time of 0.012 sec in four experiments on the blood from the same three subjects. This suggests that the velocities of the reactions of CO2 are rate-limiting in the Bohr shift. Acetazolamide (10-3 m) slowed the rate of the Bohr shift to less than one-seventh; no measurable change in O2 tension occurred until about 0.03 sec. measurable change in O2 tension occurred until about 0.03 sec. Submitted on July 2, 1962