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標題: Proton pumping inorganic pyrophosphatase of endoplasmic reticulum-enriched vesicles from etiolated mung bean seedlings
作者: Kuo, S.Y.
Chien, L.F.
Hsiao, Y.Y.
Van, R.C.
Yan, K.H.
Liu, P.F.
Mao, S.J.
Pan, R.L.
關鍵字: endoplasmic reticulum;H+-pyrophosphatase;proton translocation;tonoplast;vacuole;vacuolar h+-pyrophosphatase;vigna-radiata l;submitochondrial;particles;membrane pyrophosphatase;tonoplast;plant;purification;atpases;localization;inhibition
Project: Journal of Plant Physiology
期刊/報告no:: Journal of Plant Physiology, Volume 162, Issue 2, Page(s) 129-138.
Endoplasmic reticulurn (ER)-enriched vesicles from etiolated hypocotyts of mung bean seedlings (Vigna radiata) were successfully isolated using Ficoll gradient and two-phase (polyethylene glycol-dextran) partition. The ER-enriched vesicles contained inorganic pyrophosphate (PPi) hydrolysis and its associated proton translocating activities. Antiserum prepared against vacuolar H+-pyrophosphatase (V-PPase, EC did not inhibit this novel pyrophosphatase-dependent proton translocation, excluding the possible contamination of tonoptast vesicles in the ER-enriched membrane preparation. The optimal ratios of Mg2+/PPi (inorganic pyrophosphate) for enzymatic activity and PPj-dependent proton translocation of ER-enriched vesicles were, higher than those - of vacuolar membranes. The PPj-dependent Proton translocation of ER-enriched vesicles absolutely required the presence of monovalent cations with preference for K but could be inhibited by a common PPase inhibitor, F-. Furthermore, ER H+-pyrophosphatase exhibited some similarities and differences to vacuolar H+-PPases in cofactor/substrate ratios, pH profile, and concentration dependence of F-, imidodiphosphate (a PPj anatogue), and various chemical modifiers.
ISSN: 0176-1617
DOI: 10.1016/j.jplph.2004.07.007
Appears in Collections:期刊論文

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