The inhibition of oxygen production and the uncoupling of electron transport in photosynthesis in chloroplasts by substituted thiophens
| Autor: | R.P.F. Gregory |
|---|---|
| Rok vydání: | 1974 |
| Předmět: |
Chloroplasts
Time Factors Uncoupling Agents Biophysics Photophosphorylation Electron donor Thiophenes Oxidative phosphorylation Photochemistry Biochemistry Electron Transport Structure-Activity Relationship chemistry.chemical_compound Diphenylcarbazide Photosynthesis Cyanides Chemistry Hydrazones Oxygen evolution Cell Biology Plants Electron transport chain Oxygen Chloroplast Kinetics Energy Transfer Diuron Phosphorus Radioisotopes Mathematics |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Bioenergetics. 368:228-234 |
| ISSN: | 0005-2728 |
| DOI: | 10.1016/0005-2728(74)90151-0 |
| Popis: | 3-Acyl-5-arylidene-4-hydroxy-2,5-dihydro-2-oxothiophens, known to inhibit mitochondrial oxidative phosphorylation, are potent inhibitors of electron transport, and uncouplers of photophosphorylation, in chloroplasts. The binding of these reagents to the chloroplast is reversible. The effects are increased by electron-withdrawing substituents in the aryl group, and the lowest inhibitor constant recorded was 0.3 μM. Kinetic studies showed that the sensitive site corresponded to some 300 chlorophyll molecules. In contrast to the action of 3-(3,4-dichlorophenyl)-1,1-dimethylurea, the inhibitor constant for the most potent oxothiophen was not increased when diphenylcarbazide was used as an alternative electron donor to System II in place of water. Comparisons were made with the weak-acid type of uncoupling reagent. It is suggested that the site of action of the oxothiophens lies between the point of action of diphenylcarbazide and the quinone pool in System II, and is distinct from its uncoupling action is System I. |
| Databáze: | OpenAIRE |
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