The interaction of the (Na+,K+)-ATPase of erythrocyte ghosts with ouabain

Lishko, V. K.; Malysheva, M. K.; Grevizirskaya, T.I.

doi:10.1016/0005-2736(72)90227-1

Cited by 5 publications

(3 citation statements)

References 8 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The difference between ATP and Pl containing ghosts in the values of numbers of ouabain molecules bound is presumably referable to the differences in the hemolysis conditions which obtained during their preparation. This sidedness of action of Pi on ouabain binding has also been observed independently by Lishko et al (1972).…”

Section: Concentration and Side Dependence Of Pi Actionsupporting

confidence: 74%

Comparison of the side-dependent effects of Na and K on orthophosphate-, UTP-, and ATP-promoted ouabain binding to reconstituted human red blood cell ghosts.

Bodemann¹,

Hoffman²

1976

The Journal of General Physiology

View full text Add to dashboard Cite

This paper is concerned with analyzing the sidedness of action of various determinants which alter the rate of ouabain binding to human red blood cell ghosts. Thus, ouabain binding promoted by orthophosphate (Pi) and its inhibition by Na are shown to be due to inside Pi and inside Na. External K inhibits Pi-promoted ouabain binding and Nao acts to decrease the effectiveness of Ko. Similarly, inside uridine triphosphate (UTPi) stimulates the rate of ouabain binding which can be antagonized by either Nai or Ko acting alone. The actions of Nai and Ko are different when ouabain binding is promoted by Pi and UTPi compared to inside adenosine triphosphate (ATPi). With ATPi, the ouabain binding rate is only affected when Nai and Ko are both present. Possible differences in the mechanism of action of K and Na on Pi-and UTP-promoted binding are discussed in the light of their sidedness of action.

show abstract

Section: Concentration and Side Dependence Of Pi Actionsupporting

confidence: 74%

Comparison of the side-dependent effects of Na and K on orthophosphate-, UTP-, and ATP-promoted ouabain binding to reconstituted human red blood cell ghosts.

Bodemann¹,

Hoffman²

1976

The Journal of General Physiology

View full text Add to dashboard Cite

show abstract

“…Ghosts containing Pi were assayed in the presence of Pi in the external medium to prevent loss from the ghosts through the anion exchange pathway. It is known that external Pi does not affect the rate of ouabain binding to resealed ghosts (Lishko et al, 1972 ;Bodemann and Hoffman, 1976b) . The ouabain binding rate was negligible in comparison with ghosts replete with ATP, but still exceeded the nonspecific binding measured in the presence of 103-fold excess of unlabeled ouabain .…”

Section: Resultsmentioning

confidence: 99%

“…The rate of [3H]ouabain binding was influenced by changes of the intracellular Na + and K+ concentrations, which suggested a conformational dependence of the ouabain receptor similar to or affected by the Na+,K+ pump (Joiner and Lauf, 1978c) . Although others have examined the effect of various ligands on ouabain binding in resealed human erythrocyte ghosts (Lishko et al ., 1972 ;Bodemann and Hoffman, 1976a-c), no study has yet determined directly the specificity of ouabain for the Na+,K+ pump in these model membranes. Moreover, results obtained in resealed ghosts correlating the rate of ouabain binding with the turnover of the Na+,K + pump (Bodemann and Hoffman, 1976a) contradict those obtained in intact human and sheep erythrocytes (Joiner and Lauf, 1978c), as well as those reported for purified membrane enzyme preparations (Wallick and Schwartz, 1974 ;Lindenmayer et al ., 1974) .…”

Section: Introductionmentioning

confidence: 99%

[3H]Ouabain binding and Na+, K+-ATPase in resealed human red cell ghosts.

Shoemaker¹,

Lauf²

1983

The Journal of General Physiology

View full text Add to dashboard Cite

The interaction of the cardiac glycoside [3H]ouabain with the Na+,K+ pump of resealed human erythrocyte ghosts was investigated . Binding of [3H]ouabain to high intracellular Na' ghosts was studied in high extracellular Na' media, a condition determined to produce maximal ouabain binding rates. Simultaneous examination of both the number of ouabain molecules bound per ghost and the corresponding inhibition of the Na +,K+-ATPase revealed that one molecule of [3H]ouabain inhibited one Na +,K+-ATPase complex. Intracellular magnesium or magnesium plus inorganic phosphate produced the lowest ouabain binding rate . Support of ouabain binding by adenosine diphosphate (ADP) was negligible, provided synthesis of adenosine triphosphate (ATP) through the residual adenylate kinase activity was prevented by the adenylate kinase inhibitor Ap5A . Uridine 5'-triphosphate (UTP) alone did not support ouabain binding after inhibition of the endogenous nucleoside diphosphokinase by trypan blue and depletion of residual ATP by the incorporation of hexokinase and glucose. ATP acting solely at the high-affinity binding site of the Na+,K+ pump (K m -1 jLM) promoted maximal [3H]ouabain binding rates. Failure of 5'-adenylyl-,8-y-imidophosphate (AMP-PNP) to stimulate significantly the rate of ouabain binding suggests that phosphorylation of the pump was required to expose the ouabain receptor .

show abstract