Open AccessCharacterization of Vacuolar Malate and K+ Channels under Physiological Conditions
Author(s) -
Omar Pantoja,
Angela C Gelli,
Eduardo Blumwald
Publication year - 1992
Publication title -
plant physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.554
H-Index - 312
eISSN - 1532-2548
pISSN - 0032-0889
DOI - 10.1104/pp.100.3.1137
Subject(s) - characterization (materials science) , chemistry , biology , biophysics , botany , nanotechnology , materials science
Patch-clamp techniques were employed to study the electrical properties of vacuoles from sugar beet (Beta vulgaris) cell suspensions at physiological concentrations of cytoplasmic Ca(2+). Vacuoles exposed to K(+) malate revealed the activation of instantaneous and time-dependent outward currents by positive membrane potentials. Negative potentials induced only instantaneous inward currents. The time-dependent outward currents were 10 times more selective for malate than for K(+) and were completely blocked by zinc. Vacuoles exposed to KCl developed instantaneous currents when polarized to positive or negative membrane potentials. The time-dependent outward channels could serve as the route for the movement of malate into the vacuole, whereas K(+) could move through the time-independent inward and outward channels.