Molecular weight of Na, K-ATPase approximated by the radiation inactivation method

Nakao, Makoto; Nagano, Kei; Nakao, Toshiko; Mizuno, N.; Tashima, Y.; Fujita, Masatoshi; Maeda, Hiroshi; Matsudaira, Hiromichi

doi:10.1016/0006-291x(67)90526-8

Cited by 33 publications

(10 citation statements)

References 8 publications

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“…The Na, K-ATPase is believed to be a complex consisting of two 100,000 mol wt catalytic subunits and two 37,000 mol wt noncatalytic glycoproteins (14,16,19,22) while a trimeric (26) or tetrameric (24) arrangement of 100,000 mol wt subunit has been suggested for the gastric mucosal H, K-ATPase. Recent studies have also suggested a dimeric structure for both the Ca-ATPase of the SR3 ( (14), and the Ca-ATPase of the SR (9), evidence has been presented which indicates that the minimal unit of ATP hydrolytic activity is a 100,000 mol wt catalytic subunit (and a 37,000-mol wt glycoprotein in the case of Na, K-ATPase); however, it is unclear whether or not this is also the minimal unit which can couple ATP hydrolysis to ion transport (9,14).…”

Section: Resultsmentioning

confidence: 99%

Target Molecular Size of the Red Beet Plasma Membrane ATPase

Briskin¹,

Thornley

Roti-Roti

1985

Plant Physiol.

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Section: Resultsmentioning

confidence: 99%

Target Molecular Size of the Red Beet Plasma Membrane ATPase

Briskin¹,

Thornley

Roti-Roti

1985

Plant Physiol.

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“…Similarities in the kinetics of cation and of glucose transport hinted that a similar type of model might explain transport in these two systems. We thus developed a tentative model for Na+ and K+ transport, based on accumulated experimental data concerning the behavior of the system as a cation transporter (5)(6)(7)(8)(9)(10)(11), as a (Na + K)-activated ATPase (12)(13)(14)(15)(16)(17)(18)(19)(20), and as a K-activated phosphatase (12,21). Much of the data is indirect, and our model cannot yet account for all the experimental data.…”

mentioning

confidence: 99%

A Model for Active Transport of Sodium and Potassium Ions as Mediated by a Tetrameric Enzyme

Stein

Lieb

Karlish

et al. 1973

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

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A new model is proposed for the system that actively transports sodium and potassium ions across animal-cell membranes. The model is based on the physical and chemical properties of transport-associated adenosine triphosphatase (EC 3.6.1.3) and on the kinetics of ion movements mediated by the system. Transport is postulated to occur by internal transfer of cations across a protein tetramer embedded in the cell membrane. The protein tetramer can exist in either of two forms of identical energy; transport occurs as a result of the sequential "flipping" from one conformation to the other. The conformation change results in the interchanging of the affinities of cation-binding sites associated with different subunits of the tetramer, with a concomitant splitting of adenosine triphosphate.Miodels for the mechanism of action of the system that actively transports sodium (Na+) and potassium (K+) ions across cell membranes have often involved diffusible carriers or proteins undergoing conformational changes (1). We recently put forward a model for glucose transport in human erythrocytes, involving conformational changes within a protein tetramer embedded in the cell membrane (2-4). Similarities in the kinetics of cation and of glucose transport hinted that a similar type of model might explain transport in these two systems. We thus developed a tentative model for Na+ and K+ transport, based on accumulated experimental data concerning the behavior of the system as a cation transporter (5-11), as a (Na + K)-activated , and as a K-activated phosphatase (12,21). Much of the data is indirect, and our model cannot yet account for all the experimental data. Nevertheless, we propose it now because it is ani essentially new model and it suggests, therefore, several interesting new experiments.Physical approach toward the new model

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“…The 40 kr level had little effect on periodicity but the 100 kr level largely eliminated the periodicity. The levels of irradiation which are believed to disrupt molecules of the size of nucleic acids (40 and 100 kr) (5,11) had the least effect on exudation and the level which disrupts molecules the size of some enzymes (500 kr) (9,12) had the greatest effect on exudation; but irradiation levels which disrupt nucleic acids did have some effect.…”

Section: Wallace Ashcroft Leo and Wallacementioning

confidence: 89%

“…This is a very high dosage but evidently not high enough to decrease some respiratory enzymes (12). Chromosomes and nucleic acids in plants are inactivated generally at much lower levels (5,11). The present studies on gamma irradiation of tobacco roots were undertaken in an attempt to substantiate the possible implication of the need for new enzyme synthesis for the exudation process as indicated by the effects of cycloheximide.…”

mentioning

confidence: 99%

“…Gamma irradiation has been used as a means for determining molecular weight sizes of intermediate-and large-sized biological molecules (5,11). Since actinomycin D, an inhibitor of nucleic acid synthesis, has been suggested as one means of interfering with diurnal periodicity of exudation (8), it may prove possible to determine further with gamma irradiation whether or not molecules as large as the nucleic acids are directly or indirectly involved in the diurnal periodicity of exudation.…”

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confidence: 99%

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Effect of Cycloheximide, Gamma Irradiation, and Phosphorus Deficiency on Root Pressure Exudation in Tobacco

et al. 1970

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Cycloheximide drastically reduced the rate of root pressure exudation in detopped tobacco (Nicotiana tabacum L.), and the effect was more pronounced for nitrate salts in the external solution than for some other salts or when the roots were in water. Diurnal periodicity was greatly decreased, and its phase was changed. Effects began within an hour. Cation uptake was reduced by relatively low levels of cycloheximide. The effects of cycloheximide seemed to be reversible. Mild phosphorus deficiency resulted in decreased exudation rates from detopped tobacco and in no response to nitrate. Periodicity of exudation was not greatly affected by phosphorus deficiency, however. Gamma ray irradiation with a 60Co source at levels (up to 40-50 kilo-roentgens) which are considered disruptive of moderately large molecules had relatively little effect on the exudation rate. Higher levels of irradiation, which disrupt most protein molecules, decreased exudation and obscured peri-odicity. The results indicate either that new protein (or peptide) synthesis is needed for the rapid nitrate transport or that the deficiency and inhibitor disrupt cellular membranes. Phosphorus deficiency increased the sensitivity of the plants to inhibition by irradiation of the exudation process.

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Molecular weight of Na, K-ATPase approximated by the radiation inactivation method

Cited by 33 publications

References 8 publications

Target Molecular Size of the Red Beet Plasma Membrane ATPase

Target Molecular Size of the Red Beet Plasma Membrane ATPase

A Model for Active Transport of Sodium and Potassium Ions as Mediated by a Tetrameric Enzyme

Effect of Cycloheximide, Gamma Irradiation, and Phosphorus Deficiency on Root Pressure Exudation in Tobacco

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