Estimation of Cytoplasmic Free Mg^+ Levels and Phosphorylation Potentials in Mung Bean Root Tips by In Vivo ^<31>P NMR Spectroscopy

NDLデジタルコレクション NDLデジタルコレクション Web Site 被引用文献8件

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公開日
1988-09
公開者
Japanese Society of Plant Physiologists

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説明

The cytoplasmic [MgATP]/[ATP]_<free> ratios, free Mg^<2+> concentrations, and phosphorylation potentials in mung bean [Vigna mungo (L.) Hepper] root tip cells were investigated by ^<31>P nuclear magnetic resonance spectroscopy. ^<31>P NMR spectra show well defined peaks due to G6P, cytoplasmic P_i, vacuolar P_i, ATP, UDP-glucose and nicotinamide adenine nucleotides. The concentrations of phosphorus metabolites were determined from quantitative ^<31>P NMR spectra. The [MgATP]/[ATP]_<free> ratio was 9.45. Accordingly, about 90% of the cytoplasmic ATP was complexed to Mg^<2+>. Utilizing the dissociation constant (K_d) determined for MgATP, the cytoplasmic free Mg^<2+> concentration was estimated to be 0.4 mM. The NMR-derived phosphorylation potential, [ATP]/([ADP][P_i]), was 960 M^<-1>. The sodium azide treatment decreased the [ATP]/[ADP] ratio and the phosphorylation potential, and increased the [Mg^<2+>]_<free>. Metabolic inhibi-tion may have been enhanced by an increase in [Mg^<2+>]_<free> and a decrease in the free energy change for ATP hydrolysis, which resulted due to a decrease in the ATP level.

収集根拠 : NII-ELS
資料形態 : テキストデータ
コレクション : 国立国会図書館デジタルコレクション > 電子書籍・電子雑誌 > 学術機関 > 学協会
著者所属: Department of Instrumentation Engineering, Faculty of Science and Technology, Keio University
著者所属: Department of Instrumentation Engineering, Faculty of Science and Technology, Keio University:(Present)National Food Research Institute

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