A comparative study of the kinetics of the Bohr effect in vertebrates.

1. The kinetics of the Bohr effect and the role of carbonic anhydrase were studied in a series of representative vertebrates using a continuous flow rapid reaction apparatus. 2. The rates of the Bohr effect in vertebrates are very similar, and differences among classes are manifestations of the ambient temperature. 3. Complete carbonic anhydrase inhibition causes a fifteen to fortyfold reduction in the rate of the Bohr effect, sufficient to abolish its occurrence within capillary transit. 4. There is a twenty-three-fold (duck) to 360-fold (man) excess of carbonic anhydrase activity in vertebrate red cells for the normal generation of the Bohr effect. 5. When carbonic anhydrase is inhibited and CO2 hydration becomes rate limiting, the stoichiometry of the Bohr effect (delta log pO2/delta pH) is revealed in the ratio of the rates of proton formation in red cells to O2 release from haemoglobin.