Variation of Phosphoenolpyruvate Carboxylase Activity in Dunaliella Associated with Changes in Atmospheric CO2 Concentration

Publisher Website
Google Scholar
Abstract
In Dunaliella tertiolecta, D. bioculata and D. viridis the activities of phosphoenolpyruvate carboxylase and carbonic anhydrase were higher in the cells grown in ordinary air (low-CO2 cells) than in those grown in air enriched with 1–5% CO2 (high-CO2 cells), whereas in Porphyridium cruentum R-1 there was no difference in phosphoenolpyruvate carboxylase activity between these two types of cells. Apparent Km(NaHCO3) values for photosynthesis in low-CO2 cells of all species tested were smaller than those in high-CO2 cells. Most of the 14C was incorporated into 3-phosphoglycerate, sugar mono- and di-phosphates during the initial periods of photosynthetic NaH14CO3 indicating that both types of cells in D. tertiolecta are C3 plants.