Salt-Stimulated Adenosine Triphosphatases from Carrot, Beet, and Chara Australis

Atkinson, Joanna; Polya, GM

doi:10.1071/bi9671069

Cited by 56 publications

(28 citation statements)

References 8 publications

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“…However, stimulation was only 4-33% greater than that produced by Na+ alone; the monovalent cation stimulation did not require Mg2+; and the nucleotide specificity of the activity was not, apparently, determined. Other plant material has yielded presumptive monovalent cation activated-ATPase activities, which, on more careful analysis, were actually found to be salt-stimulated acid phosphatase activities (12).…”

Section: Discussionmentioning

confidence: 99%

Synergistically Stimulated (Na ⁺ ,K ⁺ )-Adenosine Triphosphatase from Plasma Membrane of a Marine Diatom

Sullivan

Volcani

1974

Proc. Natl. Acad. Sci. U.S.A.

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An ATP-hydrolyzing activity with the properties of a Mg2+-dependent (Na+,K+)-ATPase (ATP phosphohydrolase, EC 3.6.1.3) from a 20-fold purified plasma membrane fraction of the marine diatom, Nitxschia alba is described.The basal activity requires Mg2+ and further stimulation by Na+ or Na+ plus K+ is dependent on the presence of Mg2+; Mn2+ or Co2+ can partially substitute for the divalent cation requirement but Ca2+'equimolar with Mg"+ inhibits the activity by 54%. ATP is the preferred substrate for the Na+ plus K+ stimulated activity, while CTP, UTP, and ADP are only slightly hydrolyzed. The apparent Km is 8 X 10-' M ATP.The ATP hydrolysis-rate is dependent on the relative concentrations of Na+ and K+; the Ko.5 for Na+ and K+ are 2 mM and 50 mM, respectively. Basal activity is synergistically stimulated by Na+ plus K+ only at certain ion concentrations and shows a strong specificity for both cations.In the presence of Na+ at 5 mM and K+ at 350 mM, the ATPase is completelyinhibited by p-chloromercuric benzoic acid 10-4 M, N-ethyl maleimide 10-8 M, and iodoacetamide 10-2 M, but is insensitive to ouabain at 10-7 to 10-8 M.This study demonstrates for the first time that algal plasma membrane contains an ATPase that is synergistically stimulated by Na+ and K+.

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Section: Discussionmentioning

confidence: 99%

Synergistically Stimulated (Na ⁺ ,K ⁺ )-Adenosine Triphosphatase from Plasma Membrane of a Marine Diatom

Sullivan

Volcani

1974

Proc. Natl. Acad. Sci. U.S.A.

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“…It has also been shown that an ATPase is intimately involved in this ATP-driven reaction (33). The existence of ion-sensitive ATPases in plant tissues has been reported recently for several plant species (2,4,6,8,11,13,15,21,26,32); however, none of these reports has shown the enzyme to have any relationship to ion transport. We (8) other plant species which possess different rates of ion transport, and the results provide correlative evidence for a role of the ATPase (and therefore ATP) in the energy-dependent transport of Rb+ and K+.…”

Section: Introductionmentioning

confidence: 99%

Correlation between Ion Fluxes and Ion-stimulated Adenosine Triphosphatase Activity of Plant Roots

1970

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The energy-dependent influx of Rb+ into excised roots of corn, wheat, and barley has been determined and compared to the Rb+-stimulated ATPase activity of membrane fractions obtained from root homogenates of these species. The external Rb+ concentrations studied were in the range of 1 to 50 mM. (17,19,20) in roots, it would seem that ATP could also serve as the actual energy source for transport. In green algae it has been concluded that anion transport is more closely linked to the photosynthetic electron transport process whereas cation transport is coupled to ATP formation and utilization (25,30,31).In animal tissues it has been shown directly that ATP could provide the necessary energy for Na+ transport (5, 18). It has also been shown that an ATPase is intimately involved in this ATP-driven reaction (33). The existence of ion-sensitive ATPases in plant tissues has been reported recently for several plant species (2,4,6,8,11,13,15,21,26,32); however, none of these reports has shown the enzyme to have any relationship to ion transport. We (8) other plant species which possess different rates of ion transport, and the results provide correlative evidence for a role of the ATPase (and therefore ATP) in the energy-dependent transport of Rb+ and K+. MATERIALS AND METHODSPlant Culture. Roots from 4-day-old, dark-grown wheat (Triticum vulgare, 59 X 844), corn (Zea mays, WF9 X M14), and barley (Hordeum vulgare var. Arivat) were used. The seeds were placed between layers of cheesecloth on stainless steel screens 2 cm above a 0.2 mm CaSO4 solution with gentle aeration. All plants were kept at 25 2 C during the 4-day growing period.Influx Experiments. Rubidium influx was determined with 88Rb. Roots were excised and washed three times in approximately 250 ml of distilled water. The terminal 6 cm of five roots were cut into 1.5-cm segments and incubated in 50 ml of 0.5 mM CaSO4 plus the desired concentration of RbCl for 30 min. Solutions were maintained at 30 C during the absorption period and gentle aeration was provided. The experiments were terminated by rapid filtration on Buchner funnels. The root segments were rinsed for 30 sec with approximately 10 ml of an ice-cold washing solution (0.5 mm CaSO4-5 mm RbCl) and then placed into ice-cold washing solution for an additional 30 min. The roots were finally rinsed with the wash solution, placed in tared stainless steel planchets and weighed. Root tissue was ashed at 500 C for 1 hr and ash was moistened with 0.25 ml of 1% Photoflo, dried, and counted for radioactivity in a gas-flow counter.ATPase Experiments. The ATPase experiments were basically as described previously (8). Roots were excised and washed three times in approximately 250 ml of deionized water. The roots were chilled in cold deionized water for 15 min prior to grinding in a mortar and pestle with 100 ml of 0.25 M sucrose, 0.003 M EDTA, 0.01 M tris, pH 7.5. The tissue was ground vigorously for 45 sec, strained through four layers of cheesecloth, and finally diluted with 200 ml of 0.25 M sucrose. ...

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“…Plant workers have concentrated on identifying a corresponding microsomal Na+-K+-ATPase activity. Early work was complicated because of a highly active acid phosphatase and the so-called ATPases were generally characterized by (1,3,4,6,10): (a) low pH optima; (b) lack of substrate specificity; (c) This paper describes the separation and properties of an ATPase from the microsomal fraction of turnip, which requires Mg2+ and is stimulated by a variety of ions with specificity for the anion. The activity, which is concentrated in the smooth membrane fractions of the microsomes, is interpreted as an ion-translocating ATPase.…”

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confidence: 99%

“…Plant workers have concentrated on identifying a corresponding microsomal Na+-K+-ATPase activity. Early work was complicated because of a highly active acid phosphatase and the so-called ATPases were generally characterized by (1,3,4,6,10): (a) low pH optima; (b) lack of substrate specificity; (c) also being present in the soluble supernatant fraction; (d) inhibition by Mg2+; (e) stimulation (but not synergistically) by Na+ and K+; (f) insensitivity to ouabain. Atkinson and Polya (1) concluded that the activity in carrot, beet, and Chara was entirely due to acid phosphatase.…”

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confidence: 99%

Salt-stimulated Adenosine Triphosphatase from Smooth Microsomes of Turnip

Rungie

Wiskich²

1973

Plant Physiol.

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The turnip (Brassica rapa L.) microsome fraction contains both a Mg2-inhibited acid phosphatase and a salt-stimulated Mg2+-activated ATPase. However, as the pH optimum of the ATPase was 8.0 to 8.5, the acid phosphatase activity could be eliminated by assaying at or above pH 7.8. The ATPase was concentrated in a fraction equivalent to the smooth microsomal membranes and was not due to fragments of mitochondria. The salt-stimulated activity showed specificity for anions rather than cations. The activity was further stimulated by carbonyl cyanide m-chloro-phenylhydrazone (CCCP), 2, 4-dinitrophenol, valinomycin, nigericin, and NH4C1. There was a synergistic effect between CCCP and valinomycin. Activity was insensitive to oligomycin phlorizin, ouabain, and atractylate. Based on similarity to the chloroplast ATPase, it was proposed that this ATPase was situated on the outside of the vesicle.It is suggested that the ATPase is involved in the movement of ions, particularly anions, and may be related to the anion accumulation mechanism, which is known to occur across the tonoplast of such tissues.Salt-stimulated ATPases have been studied in both plant and animal tissue homogenates in an effort to establish the mechanism of cellular ion transport. An animal microsomal ATPase which requires Mg2+ and is synergistically stimulated by Na+ and K+ has been well characterized (25). However, this activity has now been shown to be concentrated in the plasma membranes which sediment with the endoplasmic reticulum membranes and can be largely separated from them using density gradients (2, 9). Plant workers have concentrated on identifying a corresponding microsomal Na+-K+-ATPase activity. Early work was complicated because of a highly active acid phosphatase and the so-called ATPases were generally characterized by (1,3,4,6,10): (a) low pH optima; (b) lack of substrate specificity; (c) This paper describes the separation and properties of an ATPase from the microsomal fraction of turnip, which requires Mg2+ and is stimulated by a variety of ions with specificity for the anion. The activity, which is concentrated in the smooth membrane fractions of the microsomes, is interpreted as an ion-translocating ATPase. An attempt is made to correlate the properties of this ATPase with those of the ion accumulation process of intact plant cells. MATERIALS AND METHODSCommercially obtained white turnip (Brassica rapa L.) (600 g) was homogenized in a Braun juice extractor into 40 ml of 0.3 M sucrose containing 1 g of bovine serum albumin (fraction V powder). The pH was kept at 7.4 during homogenization by the dropwise addition of 1 M tris. The mixture was strained through muslin and centrifuged at 27,000g (maximum) for 15 min to remove cell debris, mitochondria, and the larger mitochondrial fragments. The supernatant was then centrifuged at 78,000g (average) for 90 min to sediment the microsomes. Fractionation of the microsomes followed the method of Glauman and Dallner (9). The microsomal pellet was resuspended in 90 ml of 0.25 M sucr...

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Salt-Stimulated Adenosine Triphosphatases from Carrot, Beet, and Chara Australis

Cited by 56 publications

References 8 publications

Synergistically Stimulated (Na ⁺ ,K ⁺ )-Adenosine Triphosphatase from Plasma Membrane of a Marine Diatom

Synergistically Stimulated (Na ⁺ ,K ⁺ )-Adenosine Triphosphatase from Plasma Membrane of a Marine Diatom

Correlation between Ion Fluxes and Ion-stimulated Adenosine Triphosphatase Activity of Plant Roots

Salt-stimulated Adenosine Triphosphatase from Smooth Microsomes of Turnip

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Salt-Stimulated Adenosine Triphosphatases from Carrot, Beet, and Chara Australis

Cited by 56 publications

References 8 publications

Synergistically Stimulated (Na + ,K + )-Adenosine Triphosphatase from Plasma Membrane of a Marine Diatom

Synergistically Stimulated (Na + ,K + )-Adenosine Triphosphatase from Plasma Membrane of a Marine Diatom

Correlation between Ion Fluxes and Ion-stimulated Adenosine Triphosphatase Activity of Plant Roots

Salt-stimulated Adenosine Triphosphatase from Smooth Microsomes of Turnip

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Synergistically Stimulated (Na ⁺ ,K ⁺ )-Adenosine Triphosphatase from Plasma Membrane of a Marine Diatom

Synergistically Stimulated (Na ⁺ ,K ⁺ )-Adenosine Triphosphatase from Plasma Membrane of a Marine Diatom