Abstract
This chapter focuses on inorganic carbon uptake by cyanobacteria. The ability to concentrate inorganic carbon (Ci) within their cells enables cyanobacteria to compensate for the discrepancy between the Km(CO2) of ribulose-bisphosphate carboxylase (200 μM) and the concentration of dissolved CO2 in equilibrium with air (10 μM). This ability to accumulate Ci internally is light dependent and develops as a function of the concentration of CO2 experienced by the cells during growth. The rate of Ci uptake as well as the extent of accumulation is far greater in cells adapted to the air level of CO2 then in cells grown at elevated CO2 concentration, with the result that the apparent photosynthetic affinity for CO2 shown by the former cells is considerably higher. The extent of Ci accumulation is far greater than would be predicted on the basis of passive penetration of Ci species along their electrochemical potential gradient with subsequent interspecies equilibration according to intracellular pH. Two major questions have been addressed in the study of the CO2 concentrating mechanism: the nature of the Ci concentrating system and the mechanisms involved in the adaptation to varying levels of CO2. The chapter briefly reviews the major experimental approaches taken to investigate the former.
Original language | English |
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Pages (from-to) | 534-539 |
Number of pages | 6 |
Journal | Methods in Enzymology |
Volume | 167 |
Issue number | C |
DOIs | |
State | Published - Jan 1988 |