[Carbonic anhydrase of blue-green alga Spirulina platensis].

Carboanhydrase (carbonate-hydroliase EC 4.2.1.1.) is found in the extract of Spirulina platensis cells. A linear dependency of the enzyme activity on the protein concentration; pH optimum is found to be 8.0. Specific activity of carboanhydrase is 3 muM/min-mg of protein under the concentration of CO2 of 4-10(-3) M, appearing Michelis constant being 4.9-10(-3) M. The enzyme was stabilized with 10 mM of cisteine, its activity was inhibited by 50% with sulphanylamide (1-10(-5) M), acetazolamide (8--10(-7) M) and Cl- ions (5-10(-2) M). The activity of carboanhydrase, as well as the rate of NaH14CO3 fixation, depended on the pH value of cultural medium.