Characterization of a Chloroplast Inner Envelope K+ Channel
نویسندگان
چکیده
منابع مشابه
K+-conducting ion channel of the chloroplast inner envelope: functional reconstitution into liposomes.
Potassium flux between the chloroplast stroma and cytoplasm is known to be indirectly linked to H+ countertransport and, hence, stromal pH and photosynthetic capacity. The specific molecular mechanism that facilitates K+ flux across the chloroplast envelope is not known and has been a source of controversy for well over a decade. The objective of this study was to elucidate the nature of this e...
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The stromal pH of the chloroplast must be maintained higher than that of the surrounding cytosol for photosynthetic carbon assimilation to occur. Experimental evidence demonstrating how this is accomplished in the plant cell is lacking. In the experiments reported here, we studied H+ and K+ flux across membranes of purified chloroplast inner-envelope vesicles. We were able to demonstrate ATP-de...
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Studies were conducted to characterize ATPase activity associated with purified chloroplast inner envelope preparations from spinach (Spinacea oleracea L.) plants. Comparison of free Mg(2+) and Mg.ATP complex effects on ATPase activity revealed that any Mg(2+) stimulation of activity was likely a function of the use of the Mg.ATP complex as a substrate by the enzyme; free Mg(2+) may be inhibito...
متن کاملFerrous ion transport across chloroplast inner envelope membranes.
The initial rate of Fe(2+) movement across the inner envelope membrane of pea (Pisum sativum) chloroplasts was directly measured by stopped-flow spectrofluorometry using membrane vesicles loaded with the Fe(2+)-sensitive fluorophore, Phen Green SK. The rate of Fe(2+) transport was rapid, coming to equilibrium within 3s. The maximal rate and concentration dependence of Fe(2+) transport in predom...
متن کاملPartial purification of a nucleoside triphosphatase from the inner membrane of the chloroplast envelope of pea.
A Mg2+-NTPase has been partially purified from the inner membrane of the pea chloroplast envelope. Isolated envelope membranes were solubilized with Triton X-100 and fractionated by DEAE-Sephadex chromatography, followed by ultrafiltration and sucrose density gradient centrifugation. An approximate 35-fold increase in the specific activity of the vanadate and sodium fluoride sensitive NTPase wa...
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ژورنال
عنوان ژورنال: Plant Physiology
سال: 1994
ISSN: 0032-0889,1532-2548
DOI: 10.1104/pp.105.3.955