Mycochromone decreases ATP-driven proton translocation in plant plasma membrane- and tonoplast-enriched vesicles |
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Authors: | F MACRI A VIANELLO M C COCUCCI |
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Institution: | Institute of Plant Protection. Section of Plant Physiology and Biochemistry, University of Udine, 1-33100 Udine;Centre for the Study of Plant Cellular and Molecular Biology, CNR, I-20133 Milan, Italy |
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Abstract: | Abstract Mycochromone, a metabolite produced by Mycosphaerella rosigena, inhibits the ATP-dependent proton translocation and the ATP-generated electrical potential in pea stem tonoplast-enriched vesicles, without affecting the H+/K+ exchange induced by nigericin or an artificially imposed proton gradient. The inhibition is dependent on the time of pre-incubation and mycochromone concentration. In addition, mycochromone inhibits the ATP-dependent proton translocation in radish plasma membrane-enriched vesicles, though it does not alter ATPase activity (evaluated by hydrolysis of ATP) in either type of plant vesicle. Mycochromone seems to act on the H+ channels for proton translocation of the H+-pumping ATPase localized on plasmalemma and tonoplast, without affecting the catalytic site of ATP hydrolysis. |
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Keywords: | acridine Orange mycochromone oxonol VI Pisum sativum L plasma membrane-enriched vesicles proton translocation Raphanus salivas L tonoplast-enriched vesicles |
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