Carbonic Anhydrase and the State of Carbon Dioxide in Blood

Abstract

MANY physiologists hold that sodium bicarbonate is the main form in which carbon dioxide is carried in the blood, and that the elimination of the latter in the lungs is due to the reaction followed by Reaction (i) is very fast, but reaction (ii) is known to be slow. Calculations by Henriques¹ and others show indeed that (ii) is too slow to explain the observed rate of CO₂ escape in the expired air. Either then there must be a catalyst for reaction (ii) in the blood, or else some quite different chemical mechanism must operate.