Light-induced stimulation of carbonic anhydrase activity in pea thylakoids.
Stimulation of the bicarbonate dehydration reaction in thylakoid suspension under conditions of saturating light at pH 7.6-8.0 was discovered. This effect was inhibited by nigericin or the lipophilic carbonic anhydrase (CA) inhibitor ethoxyzolamide (EZ), but not by the hydrophilic CA inhibitor, acetazolamide. It was shown that the action of EZ is not caused by an uncoupling effect. It was concluded that thylakoid CA is the enzyme utilizing the light-generated proton gradient across the thylakoid membrane thus facilitating the production of CO(2) from HCO(3)(-) and that this enzyme is covered from the stroma side of thylakoids by a lipid barrier.
Moskvin
O V
OV
Institute of Basic Biological Problems, Russian Academy of Sciences, Pushchino, Russia.
Ivanov
B N
BN
Ignatova
L K
LK
Kollmeier
M A
MA
D000086:Acetazolamide / Q000494:pharmacology; D001639:Bicarbonates / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism; D002257:Carbonic Anhydrase Inhibitors / Q000494:pharmacology; D002256:Carbonic Anhydrases / Q000378:metabolism*; D004579:Electron Transport / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D005016:Ethoxzolamide / Q000494:pharmacology; D006863:Hydrogen-Ion Concentration; D007425:Intracellular Membranes / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism; D007700:Kinetics; D008027:Light; D009550:Nigericin / Q000494:pharmacology; D018532:Pisum sativum / Q000166:cytology* / Q000201:enzymology* / Q000378:metabolism; D018892:Proton-Motive Force / Q000187:drug effects; D011522:Protons; D020524:Thylakoids / Q000187:drug effects / Q000201:enzymology* / Q000378:metabolism; D014475:Uncoupling Agents
D001639:Bicarbonates; D002257:Carbonic Anhydrase Inhibitors; D011522:Protons; D014475:Uncoupling Agents; D002245:Carbon Dioxide; D002256:Carbonic Anhydrases; D000086:Acetazolamide; D009550:Nigericin; D005016:Ethoxzolamide