Evidence for an Amiloride-Inhibited Mg2+/2H+ Antiporter in Lutoid (Vacuolar) Vesicles from Latex of Hevea brasiliensis
| Autor: | Jean D'Auzac, Christophe Brugidou, Zakia Amalou, Pierre Trouslot, Rémy Gibrat |
|---|---|
| Přispěvatelé: | Biochimie et Physiologie Moléculaire des Plantes (BPMP), Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Centre international d'études supérieures en sciences agronomiques (Montpellier SupAgro)-Institut National de la Recherche Agronomique (INRA)-Institut national d’études supérieures agronomiques de Montpellier (Montpellier SupAgro), Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro) |
| Rok vydání: | 1992 |
| Předmět: |
inorganic chemicals
0106 biological sciences PH Physiology Antiporter PHYSIOLOGIE VEGETALE Plant Science Vacuole PROTON 01 natural sciences [SDV.GEN.GPL]Life Sciences [q-bio]/Genetics/Plants genetics 03 medical and health sciences Valinomycin chemistry.chemical_compound Proton transport Genetics medicine ComputingMilieux_MISCELLANEOUS 030304 developmental biology Membrane potential LUTOIDE 0303 health sciences Vesicle Membrane transport Amiloride LATEX MAGNESIUM Biochemistry chemistry Biophysics ETUDE EXPERIMENTALE ACIDIFICATION 010606 plant biology & botany medicine.drug |
| Zdroj: | Plant Physiology Plant Physiology, American Society of Plant Biologists, 1992, 100, pp.255-260. ⟨10.1104/pp.100.1.255⟩ |
| ISSN: | 1532-2548 0032-0889 |
| DOI: | 10.1104/pp.100.1.255 |
| Popis: | Lutoids represent a lysosomal microvacuolar compartment of rubber-tree (Hevea brasiliensis) latex. We observed acidification of isolated vesicles after imposing an outward Mg2+ diffusion gradient and dissipation of a preformed pH gradient in the presence of exogenous Mg2+. These results suggest the presence of a Mg2+/H+ antiporter. The maximum Mg2+/H+ exchange rate was observed at pH 8.5. The Km values for Mg2+ (2.6 mm) were identical for both influx and efflux experiments. When membrane potential was clamped at zero with K+ and valinomycin, the response of the membrane potential probe oxonol VI showed that the Mg2+/H+ exchange was electroneutral. Mg2+/H+ exchange was inhibited by amiloride and imipramine. Both the inhibiting concentration range and the Km for Mg2+ are similar to those reported for the Mg2+/2Na+ antiporter in animals cell. These data are consistent with the existence of a Mg2+/2H+ antiporter in a plant tonoplast. |
| Databáze: | OpenAIRE |
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