Effect of vanadate on proton-sucrose cotransport in Ricinus cotyledons
The effects of orthovanadate on the uptake of sucrose by Ricinus cotyledons and on sucrose-coupled proton influx were measured in order to gain insight into the relationship to the plasma membrane proton pump. Vanadate had no effect on short-term sucrose uptake. In long-term experiments (> 30 min) sucrose uptake was progressively inhibited, but only at high external sucrose concentrations. Vanadate did not affect proton efflux pumping in the absence of sucrose and neither did it change the initial rate of sucrose-coupled proton influx. However, it enhanced the maximal level of sucrose-induced alkalization of the medium at all sucrose concentrations tested. This is interpreted as an inhibiting effect of vanadate on the proton pump that recycles protons during sucrose-proton cotransport. The sensitivity towards vanadate indicates that this proton pump is an ATPase. A second proton-translocating system, that is insensitive to vanadate, is postulated to function in the absence of sucrose.
- Research Organization:
- Cornell Univ., Ithaca, NY (United States)
- OSTI ID:
- 5898331
- Journal Information:
- Plant Physiol.; (United States), Vol. 84:3
- Country of Publication:
- United States
- Language:
- English
Similar Records
Selective production of sealed plasma membrane vesicles from red beet (Beta vulgaris L. ) storage tissue
Nonspecific nature of the vanadate inhibition of rat ileal (Na, K)-ATPase
Related Subjects
59 BASIC BIOLOGICAL SCIENCES
SACCHAROSE
MEMBRANE TRANSPORT
VANADATES
BIOLOGICAL EFFECTS
ATP-ASE
INHIBITION
PLANT CELLS
PROTONS
SEEDS
SENSITIVITY
TRANSLOCATION
UPTAKE
ACID ANHYDRASES
BARYONS
CARBOHYDRATES
DISACCHARIDES
ELEMENTARY PARTICLES
ENZYMES
FERMIONS
HADRONS
HYDROLASES
NUCLEONS
OLIGOSACCHARIDES
ORGANIC COMPOUNDS
OXYGEN COMPOUNDS
PHOSPHOHYDROLASES
SACCHARIDES
TRANSITION ELEMENT COMPOUNDS
VANADIUM COMPOUNDS
560300* - Chemicals Metabolism & Toxicology
550200 - Biochemistry