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The inhibition of the carbon concentrating mechanism of the green alga Chlorella saccharophila by acetazolamide
Author(s) -
Pollock Steve Vincent,
Colman Brian
Publication year - 2001
Publication title -
physiologia plantarum
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.351
H-Index - 146
eISSN - 1399-3054
pISSN - 0031-9317
DOI - 10.1034/j.1399-3054.2001.1110413.x
Subject(s) - acetazolamide , carbonic anhydrase , chemistry , sulfonamide , chlorella , biochemistry , transporter , intracellular , total inorganic carbon , biophysics , enzyme , medicinal chemistry , carbon dioxide , botany , biology , stereochemistry , algae , organic chemistry , physiology , gene
The effects of the carbonic anhydrase (CA) inhibitors acetazolamide (AZ) and dextran‐bound sulfonamide (DBS) on HCO 3 − ‐dependent O 2 evolution in Chlorella saccharophila were evaluated. Addition of 4 μ M AZ or 0.4 mg ml −1 DBS to photosynthesizing cells reduced the O 2 evolution rate at low dissolved inorganic carbon (DIC) concentration, decreased the size of the intracellular acid‐labile carbon pool, and decreased the apparent affinity of the cells for DIC. Measurement of the whole‐cell affinity of cells for CO 2 and HCO 3 − in the presence and absence of inhibitors indicated that active HCO 3 − transport was inhibited by AZ and DBS. The inhibition of HCO 3 − transport was independent of the inhibition of external and internal CA. These results suggest that the active uptake of HCO 3 − occurs initially by the interaction of HCO 3 − and a CA‐like transporter.