Abstract
Plasma membrane enriched vesicle fractions were isolated on discontinuous sucrose gradients from unadapted and 428 mM NaCl adapted tobacco cells (Nicotiana tabacum L. var. Wisconsin 38). The fractions collected from the 36/45 % interfaces were determined to be plasma membrane enriched based on analyses of marker enzyme activities. Kinetic properties of H+-transport (determined by [14C]-SCN- uptake) of the plasma membrane H+-ATPase of adapted cells were substantially different than those of unadapted cells. H+ transport activity of the plasma membrane H+-ATPase from NaCl adapted cells was more susceptible to substrate inhibition by free ATP (ki = 3.1 mM) than the activity of the plasma membrane H+-ATPase from unadapted cells (ki = 10 mM). The plasma membrane H+-ATPase from NaCl adapted cells exhibited an apparent Km for MgATP of 0.6 ± 0.2 mM compared with 1.76 ± 0.5 mM for the plasma membrane H+-ATPase from unadapted cells. These data indicate that the plasma membrane H+-ATPase of adapted cells can function efficiently in saline environments where increased competition for the ATP pool is presumed.
Original language | English |
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Pages (from-to) | 312-318 |
Number of pages | 7 |
Journal | Journal of Plant Physiology |
Volume | 142 |
Issue number | 3 |
DOIs | |
State | Published - 1993 |
Externally published | Yes |
Keywords
- 2-[morpholino]ethane sulfonic acid
- BTP
- Bis tris propane
- GSII
- Glucan synthase II
- Mes
- NaCl adaptation
- Nicotiana tabacum L.
- PMSF
- Phenylmethanesulfonylfluoride
- UDP-glucose
- Uridine diphosphoglucose
- plasma membrane H-ATPase
ASJC Scopus subject areas
- Physiology
- Agronomy and Crop Science
- Plant Science