Carbonic anhydrase as a tool in studying the mechanism of reactions involving H(2)CO(3), CO(2) or HCO(3)'.

arise or react. For example, when urea is acted upon by urease in a buffer solution the end products are NH+, C02, and HCO_ and the question presents itself whether C02, or HCO, or H2002 is the primary form of carbonic acid. Similar problems arise in studying the mechanism of decarboxylation of aor ,B-ketonic acids and of the bacterial fission of formic acid into H2 and C02. As Roughton and his colleagues (Meldrum & Roughton, 1933; Ferguson & Roughton, 1934; Roughton, 1935) have already pointed out, carbonic anhydrase can be used as a tool in studying this kind of problem. The present paper is an attempt. to discuss the scope ofthis tool, to elaborate the experimental conditions under which it can be used and to define the conclusions which can be drawn from various types of experiments. Applications of the method to the study ofurease and yeast carboxylase are given. Theoretical con8ideration8