The manometric determination of the activity of carbonic anhydrase under varied conditions.

The activity of carbonic anhydrase was first measured by Meldrum & Roughton (1932) with the boat-manometric method which Brinkman, Mar-garia & Roughton (1933) had developed for study of the kinetics of the reaction CO2+H20 H2CO3 in absence of enzyme. In this method a buffer solution is shaken violently with bicarbonate solution (or with a C02-containing gas phase) in a boat- shaped vessel which is flexibly connected to a U -tube manometer. The rate of CO2 output (or uptake) is followed by reading the pressure at various times after the shaking begins. The magnification of the rate, when carbonic anhydrase is added to the buffer, is taken as a measure of the activity of the enzyme. Variations and improvements in the manometric method have since been made by Stadie & O'Brien (1933), Van Goor (1934), Roughton & Booth (1938), Kiese & Hastings (1940), Kiese (1941), and Leiner (1941). gas liquid as the The influence diffusion however, for quantitatively mental recently worked out by Roughton of the stationary film theory of gas-liquid