1. Light-induced stimulation of carbonic anhydrase activity in pea thylakoids.
- Author
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Moskvin OV, Ivanov BN, Ignatova LK, and Kollmeier MA
- Subjects
- Acetazolamide pharmacology, Bicarbonates metabolism, Carbon Dioxide metabolism, Carbonic Anhydrase Inhibitors pharmacology, Electron Transport drug effects, Enzyme Activation drug effects, Ethoxzolamide pharmacology, Hydrogen-Ion Concentration, Intracellular Membranes drug effects, Intracellular Membranes enzymology, Intracellular Membranes metabolism, Kinetics, Nigericin pharmacology, Pisum sativum metabolism, Proton-Motive Force drug effects, Protons, Thylakoids drug effects, Thylakoids metabolism, Uncoupling Agents, Carbonic Anhydrases metabolism, Light, Pisum sativum cytology, Pisum sativum enzymology, Thylakoids enzymology
- Abstract
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.
- Published
- 2000
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