Effect of dicyclohexylcarbodiimide on the proton conductance of thylakoid membranes in intact chloroplast
| Autor: | G. A. Kurella, Alexander A. Bulychev, Andrianov Vk |
|---|---|
| Rok vydání: | 1980 |
| Předmět: |
Chloroplasts
Anthoceros Light ATPase Diffusion Kinetics Biophysics Analytical chemistry Biochemistry Membrane Potentials Adenosine Triphosphatases biology Chemistry food and beverages Conductance Cell Biology Darkness Plants biology.organism_classification Chloroplast Carbodiimides Dicyclohexylcarbodiimide Thylakoid biology.protein sense organs Electric potential Mathematics |
| Zdroj: | Biochimica et Biophysica Acta (BBA) - Bioenergetics. 590:300-308 |
| ISSN: | 0005-2728 |
| DOI: | 10.1016/0005-2728(80)90201-7 |
| Popis: | The effects of dicyclohexylcarbodiimide, a potent inhibitor of chloroplast ATPase, on the light-induced electric potential changes in intact chloroplasts of Peperomia metallica and of a hornwort Anthoceros sp. were investigated by means of glass microcapillary electrodes. The characteristics of potential changes induced by flashes or continuous light in chloroplasts of both species are similar except for the phase of potential rise in continuous light, which is clearly biphasic in Anthoceros chloroplasts. Dicyclohexylcarbodiimide at concentration 5 · 10 −5 M completely abolishes the transient potential undershoot in the light-off reaction but has little effect on the peak value of the photoelectric response. The membrane conductance in the light and in the dark was tested by measuring the decay kinetics of flash-generated potential in dark-adapted and preilluminated chloroplasts. In the absence of dicyclohexylcarbodiimide, preillumination causes a significant acceleration of the potential decay. The light-induced changes in the decay kinetics of flash-induced responses were abolished in the presence of dicyclohexylcarbodiimide, whereas the rate of potential decay in dark-adapted chloroplasts was not altered by dicyclohexylcarbodiimide. The results are consistent with the notion that dicyclohexylcarbodiimide diminishes H + conductance of energized thylakoid membranes by interacting with the H + channel of ATPase. The occurrence of a lag (approx. 300 ms) on the plot of potential undershoot (diffusion potential) versus illumination time might suggest the increase in H + permeability coefficient of thylakoid membrane during illumination. |
| Databáze: | OpenAIRE |
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