TONOPLAST INORGANIC PYROPHOSPHATASE IN VICIA-FABA GUARD-CELLS

Citation
Cp. Darley et al., TONOPLAST INORGANIC PYROPHOSPHATASE IN VICIA-FABA GUARD-CELLS, Planta, 206(2), 1998, pp. 272-277
Citations number
30
Categorie Soggetti
Plant Sciences
Journal title
PlantaACNP
ISSN journal
00320935
Volume
206
Issue
2
Year of publication
1998
Pages
272 - 277
Database
ISI
SICI code
0032-0935(1998)206:2<272:TIPIVG>2.0.ZU;2-L
Abstract
Lysed guard-cell protoplasts of Vicia faba L. exhibited hydrolytic act ivity characteristic of tonoplast inorganic pyrophosphatase (V-PPase; EC 3.6.1.1). Activity was inhibited by the specific V-PPase inhibitor aminomethylenediphosphonate, stimulated by K+ (K-m = 51 mM) and inhibi ted by Ca2+ (80 nM free Ca2+ was required for 50% inhibition at 0.27 m M free Mg2+). Patch-clamp measurements of electrogenic activity confir med enzyme localisation at the tonoplast. This is the first report of V-PPase activity in guard cells; its possible involvement in stomatal opening is discussed.