Carbonic Anhydrase ofChlamydomonas: Purification and Studies on its Induction Using Antiserum againstChlamydomonasCarbonic Anhydrase

摘要

Carbonic anhydrase (EC 4.2.1.1; CA) was purified by affinity chromatography from cells of the unicellular green algaChlamydomonas reinhardtiiwhich had been grown photoautotrophically in ordinary air. Antiserum raised in rabbit against this purified CA crossreacted withChlamydomonasCA but not with spinach leaf CA nor bovine erythrocyte CA. When the CO2concentration provided to the algal cells was decreased from 4to the ordinary air level (0.04), CA activity and the content of CA protein determined by the immunodiffusion test showed parallel increases. In contrast, when the CO2concentration was raised from air level to 4CO2CA activity and its content expressed on the basis of culture volume remained rather constant. These results indicate that synthesis of the CA protein is induced when the CO2concentration is lowered from 4 to 0.04during algal growth. On the other hand, the synthesis of CA stops when CO2concentration is raised from air level to 4.