Proton Pumping Pyrophosphatase in a High Density Fraction of Radish Microsomes

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概要

• 論文の詳細を見る

• Radish (Raphanus sativus L.) microsomal vesicles show a vanadate-and nitrate-insensitive, and imidodiphosphate-sensitive electrogenic transport of protons dependent upon addition of in-organic pyrophosphate (PP) or ADP. The activity is detectable in preparations from 24 h-old seedlings and increases about 3 fold in vesicles from 72 h-old seedlings. The ADP-dependent pro-ton uptake, being prevented by inorganic pyrophosphatase, used as a PP scavenging system, can be ascribed to enzymes utilizing ADP and producing PP which appears the only substrate for the proton pumping PPase. The H^+-PPase has a K_m of ca. 10 μM for the translocating function and 20 μM for the hydrolytic activity. It has a pH optimum near to 7.0 and is stimulated by certain monovalent cations (K^+, Rb^+ and Cs^+). The majority of this activity is associated with a high density (35-4% sucrose interface) fraction which is enriched for vanadate-sensitive, nitrate-insensitive ATPase activity.

• 日本植物生理学会の論文

著者

• Macri F

  Univ. Udine Udine Itary

• Macri Francesco

  Institute of Plant Protection, Section of Plant Physiology and Biochemistry, University of Udine

• Vianello Angelo

  Institute of Plant Protection, Section of Plant Physiology and Biochemistry, University of Udine

• Vianello Angelo

  Institute Of Plant Protection Section Of Plant Physiology And Biochemistry University Of Udine

関連論文

• ATP Synthesis Driven by a-Keto Acid-stimulated Alternative Oxidase in Pea Leaf Mitochondria
• Orientation of Pea Stem Mitochondrial H^+-pyrophosphatase and Its Different Characteristics from the Tonoplast Counterpart
• Proton Pumping Pyrophosphatase in a High Density Fraction of Radish Microsomes

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