Characterization of a K+-Stimulated Adenosine Triphosphatase Associated with the Plasma Membrane of Red Beet
Open Access
- 1 February 1983
- journal article
- research article
- Published by Oxford University Press (OUP) in Plant Physiology
- Vol. 71 (2) , 350-355
- https://doi.org/10.1104/pp.71.2.350
Abstract
A membrane fraction enriched with a magnesium-dependent, monovalent cation-stimulated ATPase was isolated from red beet (Beta vulgaris L.) storage roots by a combination of differential centrifugation, extraction with KI, and sucrose density gradient centrifugation. This fraction was distinct from endoplasmic reticulum, Golgi, mitochondrial, and possibly tonoplast membranes as determined from an analysis of marker enzymes. The ATPase activity associated with this fraction was further characterized and found to have a pH optimum of 6.5 in the presence of both Mg2+ and K+. The activity was substrate specific for ATP and had a temperature optimum near 40°C. Kinetics with Mg:ATP followed a simple Michaelis-Menten relationship. However the kinetics of K+-stimulation were complex and suggestive of negative cooperativity. When monovalent cations were present at 2.5 millimolarity, ATPase was stimulated in the sequence K+ > Rb+ > Na+ > Li+ but when the concentration was raised to 50 millimolarity, the sequence changed to K+ ≥ Na+ ≥ Rb+ > Li. The activity was not synergistically stimulated by combinations of Na+ and K+. The enzyme was insensitive to NaN3, oligomycin, ouabain, and sodium molybdate but sensitive to N,N′-dicyclohexylcarbodiimide, diethylstilbestrol, and sodium vanadate. Based on the similarity between the properties of this ATPase activity and those from other well characterized plant tissues, it has been concluded that this membrane fraction is enriched with plasma membrane vesicles.This publication has 14 references indexed in Scilit:
- The proton-translocating ATPase of the fungal plasma membraneBiochimica et Biophysica Acta (BBA) - Reviews on Bioenergetics, 1981
- Mg 2+ /KCl-ATPase of plant plasma membranes is an electrogenic pumpProceedings of the National Academy of Sciences, 1981
- The Structure of Proteins Involved in Active Membrane TransportAnnual Review of Biophysics and Bioengineering, 1980
- Inhibition of Adenosine Triphosphatase Activity of the Plasma Membrane Fraction of Oat Roots by DiethylstilbestrolPlant Physiology, 1979
- Purification of Plasma Membranes from Roots of BarleyPlant Physiology, 1978
- A simplification of the protein assay method of Lowry et al. which is more generally applicableAnalytical Biochemistry, 1977
- Selectivity of Alkali Cation Influx Across the Plasma Membrane of Oat RootsPlant Physiology, 1977
- Cation-stimulated Adenosine Triphosphatase Activity and Cation Transport in Corn RootsPlant Physiology, 1976
- Isolation of Plasma Membranes from Corn Roots by Sucrose Density Gradient CentrifugationPlant Physiology, 1976
- ISOLATION OF β-GLUCAN SYNTHETASE PARTICLES FROM PLANT CELLS AND IDENTIFICATION WITH GOLGI MEMBRANESProceedings of the National Academy of Sciences, 1969