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Effect of auxin on Mg<sup>++</sup>-activated and -inhibited ATPases from mung bean hypocotyls
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1974
Year
BotanyPlant BiochemistryPlant Growth RegulatorCellular PhysiologyProtein SynthesisPlant Molecular BiologyBiosynthesisBioenergeticsBioanalysisMolecular PhysiologyBiochemistryMung Bean HypocotylsIon ChannelsMembrane BiologyVivo TreatmentPlant HormonePlant MetabolismCellular EnzymologyNatural SciencesPhysiologyA AtpaseCellular BiochemistryMetabolismMedicinePlant Physiology
Mg++-activated (A) and -inhibited (B) ATPases were isolated from dark-grown mung bean hypocotyls and the effect of in vivo and in vitro IAA-treatment on these ATPases was observed. The activity of the A-ATPase, which was localized in the plasma membrane-rich fractions, was enhanced by exogenously added l0−10M IAA (ca. 35%). The stimulatory effect of in vitro IAA-treatment was particularly found in the A ATPase isolated from sections treated with 10−5M IAA for 60 min (ca. 280%). The activity of the B-ATPase, which was localized in the soluble fraction of the cell homogenate, was markedly increased by in vivo treatment with 10−7M IAA for 60 min (ca. 360%). The stimulatory effect of IAA-treatment was observed even if protein synthesis was inhibited by cycloheximide. These results suggest that the enhancement of the activities of the A- and B-ATPases caused by in vivo and in vitro IAA-treatments occur as a result of the activation of already present enzymes, rather than of the synthesis of these enzymes.