Skip to main content
SpringerLink
Log in

Fast charge translocations associated with partial reactions of the Na,K-pump: II. Microscopic analysis of transient currents

  • Articles
  • Published:
The Journal of Membrane Biology Aims and scope Submit manuscript

Summary

Nonstationary pump currents which have been observed in K+-free Na+ media after activation of the Na,K-ATPase by an ATP-concentration jump (see the preceding paper) are analyzed on the basis of microscopic reaction models. It is shown that the behavior of the current signal at short times is governed by electrically silent reactions preceding phosphorylation of the protein; accordingly, the main information on charge-translocating processes is contained in the declining phase of the pump current. The experimental results support the Albers-Post reaction scheme of the Na,K-pump, in which the translocation of Na+ precedes translocation of K+. The transient pump current is represented as the sum of contributions of the individual transitions in the reaction cycle. Each term in the sum is the product of a net transition rate times a “dielectric coefficient” describing the amount of charge translocated in a given reaction step. Charge translocation may result from the motion of ion-binding sites in the course of conformational changes, as well as from movement of ions in access channels connecting the binding sites to the aqueous media. A likely interpretation of the observed nonstationary currents consists in the assumption that the principal electrogenic step is the E1-P/P-E2 conformational transition of the protein, followed by a release of Na+ to the extracellular side. This conclusion is supported by kinetic data from the literature, as well as on the finding that chymotrypsin treatment which is known to block the E1-P/P-E2 transition abolishes the current transient. By numerical simulation of the Albers-Post reaction cycle, the proposed mechanism of charge translocation has been shown to reproduce the experimentally observed time behavior of pump currents.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  • Beaugé, L.A., Ortiz, O. 1973. Na fluxes in rat blood cells in K-free solutions.J. Membrane Biol. 13:165–184

    Google Scholar 

  • Borlinghaus, R., Apell, H.-J., Läuger, P. 1987. Fast charge translocations associated with partial reactions of the Na,K-pump: I. Current and voltage transient after photochemical release of ATP.J. Membrane Biol. 97:161–178

    Google Scholar 

  • Cantley, L.C., Carili, C.T., Smith, R.L., Perlman, D., 1984. Conformational changes of Na,K-ATPase necessary for transport.Curr. Top. Membr. Transp. 19:315–322

    Google Scholar 

  • Cornelius, F., Skou, J.C. 1985. Na+−Na+ exchange mediated by (Na++K+)-ATPase reconstituted into liposomes. Evaluation of pump stoichiometry and response to ATP and ADP.Biochim. Biophys. Acta 818:211–221

    PubMed  Google Scholar 

  • Dissing, S., Hoffman, J.F. 1983. Anion-coupled Na efflux mediated by the Na∶K pump in human red blood cells.Curr. Top. Membr. Transp. 19:693–695

    Google Scholar 

  • Eigen, M., Maass, G., 1966. Über die Kinetik der Metallkomplex-bildung der Alkali- und Erdalkaliionen in wäßrigen Läsungen.Z. Phys. Chem. 49:163–177

    Google Scholar 

  • Forbush, B., III. 1984. Na+ movement in a single turnover of the Na pump.Proc. Natl. Acad. Sci. USA 81:5310–5314

    PubMed  Google Scholar 

  • Forbush, B., III. 1985. Rapid ion movements in a single turnover of the Na+ pump.In: The Sodium Pump. I. Glynn and C.L. Ellory, editors. pp. 599–611. Company of Biologists. Cambridge, U.K.

    Google Scholar 

  • Forgac, M., Chin, G. 1981. K+-independent active transport of Na+ by the (Na++K+)-stimulated adenosine triphosphatase.J. Biol. Chem. 256:3645–3646

    PubMed  Google Scholar 

  • Forgac, M., Chin, G. 1982. Na+ transport by the (Na+)-stimulated adenosine triphosphatase.J. Biol. Chem. 257:5652–5655

    PubMed  Google Scholar 

  • Garrahan, P.J., Glynn, I.M. 1967a. The behaviour of the sodium pump in red cells in the absence of external potassium.J. Physiol. (London) 192:159–174

    Google Scholar 

  • Garrahan, P.J., Glynn, I.M. 1967b. The sensitivity of the sodium pump to external sodium.J. Physiol. (London) 192:175–188

    Google Scholar 

  • Garrhan, P.J., Glynn, I.M. 1967c. Factors affecting the relative magnitudes of the sodium: potassium and the sodium:sodium exchanges catalyzed by the sodium pump.J. Physiol. (London) 192:189–216

    Google Scholar 

  • Glynn, I.M. 1985. The Na+, K+-transporting adenosine triphosphatase.In: The Enzymes of Biological Membranes. (2nd ed.) Vol. 3: Membrane Transport. A.N. Martonosi, editor. pp. 35–114. Plenum, New York

    Google Scholar 

  • Glynn, I.M., Hara, Y., Richards, D.E. 1984. The occlusion of sodium ions within the mammalian sodium-potassium pump: Its role in sodium transport.J. Physiol. (London) 351:531–547

    Google Scholar 

  • Glynn, I.M., Karlish, S.J.D. 1976. ATP hydrolysis associated with an uncoupled sodium flux through the sodium pump: Evidence for allosteric effects of intracellular ATP and extracellular sodium.J. Physiol. (London) 256:465–496

    Google Scholar 

  • Goldschlegger, R., Karlish, S.J.D., Rephael, A., Stein, W.D. 1987. The effect of membrane potential on the mammalian sodium-potassium pump reconstituted into phospholipid vesicles.J. Physiol. (London) (in press)

  • Hegyvary, C., Post, R.L. 1971. Binding of adenosine triphosphatase to sodium and potassium ion-stimulated adenosine triphosphatases.J. Biol. Chem. 246:5234–5240

    Google Scholar 

  • Jørgensen, P.L., Collins, J.H. 1986. Tryptic and chymotryptic cleavage sites in the sequence of α-subunit of (Na++K+)-ATPase from outer medulla of mammalian kidney. Biochim. Biophys. Acta860:570–576

    PubMed  Google Scholar 

  • Jørgensen, P.L., Petersen, J. 1985. Chymotryptic cleavage of α-subunit in E1-forms of renal (Na++K+)-ATPase: Effects of enzymatic properties, ligand binding and cation exchange.Biochim. Biophys. Acta 821:319–333

    PubMed  Google Scholar 

  • Kapakos, J.G., Steinberg, M. 1985. 5-Iodoacetamidofluoresceinlabeled (Na,K)-ATPase. Steady-state fluorescence during turnover.J. Biol. Chem. 261:2090–2095

    Google Scholar 

  • Karlish, S.J.D., Glynn, I.M. 1974. An uncoupled, efflux of sodium ions from human red cells, probably associated with Na-dependent ATPase activity.Ann. N.Y. Acad. Sci. 242:461–470

    PubMed  Google Scholar 

  • Karlish, S.J.D., Kaplan, J.H. 1985. Pre-steady-state kinetics of Na+ transport through the Na,K-pump.In: The Sodium Pump. I. Glynn and C.L. Ellory, editors. pp. 501–506. Company of Biologists, Cambridge, U.K.

    Google Scholar 

  • Karlish, S.J.D., Rephaeli, A., Stein, W.D. 1985. Transmembrane modulation of cation transport by the Na,K-pump.In: The Sodium Pump. I. Glynn and C.L. Ellory, editors pp. 487–499. Company of Biologists, Cambridge, U.K.

    Google Scholar 

  • Karlish, S.J.D., Yates, D.W. 1978. Tryptophane fluorescence of (Na++K+)-ATPase as a tool for study of the enzyme mechanism.Biochim. Biophys. Acta 527:115–130

    PubMed  Google Scholar 

  • Karlish, S.J.D., Yates, D.W., Glynn, I.M. 1978. Elementary steps of the (Na++K+)-ATPase mechanism, studied with formycin nucleotides.Biochim. Biophys. Acta 525:230–251

    PubMed  Google Scholar 

  • Kennedy, B.G., DeWeer, P. 1976. Relationship between Na∶K and Na∶Na exchange by the sodium pump of skeletal muscle.Nature (London) 268:165–167

    Google Scholar 

  • Lafaire, A.V., Schwarz, W. 1986. Voltage dependence of the rheogenic Na+/K+ ATPase in the membrane of oocytes ofXenopus laevis.J. Membrane Biol. 91:43–51

    Google Scholar 

  • Läuger, P., Apell, H.-J. 1986. A microscopic model for the current-voltage behaviour of the Na,K-pump.Eur. Biophys. J. 13:309–321

    Google Scholar 

  • Läuger, P., Benz, R., Stark, G., Bamberg, E., Jordan, P.C., Fahr, A., Brock, W. 1981. Relaxation studies of ion transport systems in lipid bilayer membranes.Q. Rev. Biophys. 14:513–598

    PubMed  Google Scholar 

  • Lee, K.H., Blostein, R. 1980. Red cell sodium fluxes catalyzed by the sodium pump in the absence of K+ and ADP.Nature (London) 285:338–339

    Google Scholar 

  • Lew, V.L., Hardy, M.A., Ellory, J.C. 1973. The uncoupled extrusion of Na+ through the Na+ pump.Biochim. Biophys. Acta 323:251–266

    Google Scholar 

  • Mårdh, S. 1975. Bovine brain Na+, K+-stimulated ATP phosphohydrolase studied by a rapid-mixing technique. K+-stimulated liberation of [32P] orthophosphate from [32P] phosphoenzyme and resolution of the dephosphorylation into two phases.Biochim. Biophys. Acta 391:448–463

    PubMed  Google Scholar 

  • Mårdh, S., Lindahl, S. 1977. On the mechanism of sodium- and potassium-activated adenosine triphosphatase.J. Biol. Chem. 252:8058–8061

    PubMed  Google Scholar 

  • Mårdh, S., Post R.L. 1977. Phosphorylation from adenosine triphosphate of sodium- and potassium-activated adenosine triphosphatase.J. Biol. Chem. 252:633–638

    PubMed  Google Scholar 

  • Mårdh, S., Zetterquist, Ö. 1974. Phosphorylation and dephosphorylation reactions of bovine brain (Na++K+)-stimulated ATP phosphohydrolase studied by a rapid-mixing technique.Biochim. Biophys. Acta 350:473–483

    PubMed  Google Scholar 

  • McCray, J.A., Herbette, L., Kihara, T., Trentham, D.R. 1980. A new approach to time-resolved studies of ATP-requiring biological systems: Laserflash photolysis of caged ATP.Proc. Natl. Acad. Sci. USA 77:7237–7241

    PubMed  Google Scholar 

  • Nakao, M., Gadsby, D.C. 1986. Voltage dependence of Na translocation by the Na/K pump.Nature (London) 323:628–630

    Google Scholar 

  • Nicolas, R.A. 1984. Purification of the membrane spanning tryptic peptides of the α-polypeptide from sodium and potassium ion activated adenosinetriphosphatase labeled with 1-tritiospiro[adamantane-4,3′-diazinine].Biochemistry 23:888–898

    PubMed  Google Scholar 

  • Nørby, J.G., Jensen, J. 1971. Binding of ATP to brain microsomal ATPase. Determination of the ATP-binding capacity and the dissociation constant of the enzyme-ATP complex as a function of K+ concentration.Biochim. Biophys. Acta 233:104–116

    PubMed  Google Scholar 

  • Post, R.L., Hegyvary, C., Kume, S. 1972. Activation by adenosine triphosphate in the phosphorylation kinetics of sodium and potassium ion transport adenosine triphosphatase.J. Biol. Chem. 247:6530–6540

    Google Scholar 

  • Rephaeli, A., Richards, D., Karlish, S.J.D. 1986a. Conformational transitions in fluorescein-labled (Na,K)ATPase reconstituted into phospholipid vesicles.J. Biol. Chem. 261:6248–6254

    PubMed  Google Scholar 

  • Rephaeli, A., Richards, D., Karlish, S.J.D. 1986b. Electrical potential accelerates the E1P(Na)-E2P conformational transition of (Na,K)ATPase in reconstituted vesicles.J. Biol. Chem. 261:12437–12440

    Google Scholar 

  • Robinson, J.D., Flashner, M.S. 1979. The (Na++K+)-activated ATPase. Enzymatic and transport properties.Biochim. Biophys. Acta 549:145–176

    PubMed  Google Scholar 

  • Sachs, J.R. 1970. Sodium movements in the human red cell.J. Gen. Physiol. 56:322–341

    PubMed  Google Scholar 

  • Schuurmans-Stekhoven, F.M.A.H., Swarts, H.G.P., Pont, J.J.H.H.M. de, Bonting., S.L. 1986. Sodium and buffer cations inhibit dephosphorylation of (Na++K+)-ATPase.Biochim. Biophys. Acta 855:375–382

    PubMed  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Department of Biology, University of Konstanz, D-7750, Konstanz, Germany

    H. J. Apell, R. Borlinghaus & P. Läuger

Authors
  1. H. J. Apell
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. R. Borlinghaus
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. P. Läuger
    View author publications

    You can also search for this author in PubMed Google Scholar

Rights and permissions

Reprints and permissions

About this article

Cite this article

Apell, H.J., Borlinghaus, R. & Läuger, P. Fast charge translocations associated with partial reactions of the Na,K-pump: II. Microscopic analysis of transient currents. J. Membrain Biol. 97, 179–191 (1987). https://doi.org/10.1007/BF01869221

Download citation

  • Received:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF01869221

Key Words

Search

Navigation