Properties of the Na+-K+ pump in human red cells with increased number of pump sites (original) (raw)

Abstract

We studied the Na+/K+ pump in red cells from an obese human subject (MAJ) in which the number of pumps/cell was 10-20 times higher than normal. Through measurements of the kinetic properties of several modes of operation of the Na+/K+ pump we determined that the pumps in MAJ cells are kinetically normal. In the presence of adequate metabolic substrate the maximum rates of Na+ pumping and lactate production saturated at 60 and 12 nmol/1 cell per h, respectively. Under physiological conditions pump and "leak" Na+ fluxes were similar in MAJ and normal cells. Since internal Na+ was lower in MAJ than in normal cells (Nai+ approximately 2 and 8 mmol/1 cell, respectively), we conclude that the reduction in cell Na+ allows the Na+/K+ pump in MAJ cells to operate at lower fraction of maximum capacity and to compensate for the increased number of pumps.

128

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. BERNSTEIN R. E. Alterations in metabolic energetics and cation transport during aging of red cells. J Clin Invest. 1959 Sep;38:1572–1586. doi: 10.1172/JCI103936. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Baginski E. S., Foá P. P., Zak B. Determination of phosphate and phosphomonoesterases in biologic materials. Am J Med Technol. 1969 Aug;35(8):475–486. [PubMed] [Google Scholar]
  3. Brugnara C., Kopin A. S., Bunn H. F., Tosteson D. C. Regulation of cation content and cell volume in hemoglobin erythrocytes from patients with homozygous hemoglobin C disease. J Clin Invest. 1985 May;75(5):1608–1617. doi: 10.1172/JCI111867. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. DeLuise M., Flier J. S. Functionally abnormal Na+-K+ pump in erythrocytes of a morbidly obese patient. J Clin Invest. 1982 Jan;69(1):38–44. doi: 10.1172/JCI110439. [DOI] [PMC free article] [PubMed] [Google Scholar]
  5. Funder J. Alkali metal cation transport through the human erythrocyte membrane by the anion exchange mechanism. Acta Physiol Scand. 1980 Jan;108(1):31–37. doi: 10.1111/j.1748-1716.1980.tb06497.x. [DOI] [PubMed] [Google Scholar]
  6. Garay R. P., Garrahan P. J. The interaction of sodium and potassium with the sodium pump in red cells. J Physiol. 1973 Jun;231(2):297–325. doi: 10.1113/jphysiol.1973.sp010234. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Garrahan P. J., Glynn I. M. Facftors affecting the relative magnitudes of the sodium:potassium and sodium:sodium exchanges catalysed by the sodium pump. J Physiol. 1967 Sep;192(1):189–216. doi: 10.1113/jphysiol.1967.sp008296. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Garrahan P. J., Glynn I. M. The behaviour of the sodium pump in red cells in the absence of external potassium. J Physiol. 1967 Sep;192(1):159–174. doi: 10.1113/jphysiol.1967.sp008294. [DOI] [PMC free article] [PubMed] [Google Scholar]
  9. Garrahan P. J., Glynn I. M. The incorporation of inorganic phosphate into adenosine triphosphate by reversal of the sodium pump. J Physiol. 1967 Sep;192(1):237–256. doi: 10.1113/jphysiol.1967.sp008298. [DOI] [PMC free article] [PubMed] [Google Scholar]
  10. Glynn I. M., Hoffman J. F. Nucleotide requirements for sodium-sodium exchange catalysed by the sodium pump in human red cells. J Physiol. 1971 Oct;218(1):239–256. doi: 10.1113/jphysiol.1971.sp009612. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Glynn I. M., Lew V. L., Lüthi U. Reversal of the potassium entry mechanism in red cells, with and without reversal of the entire pump cycle. J Physiol. 1970 Apr;207(2):371–391. doi: 10.1113/jphysiol.1970.sp009067. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Glynn I. M., Lew V. L. Synthesis of adenosine triphosphate at the expense of downhill cation movements in intact human red cells. J Physiol. 1970 Apr;207(2):393–402. doi: 10.1113/jphysiol.1970.sp009068. [DOI] [PMC free article] [PubMed] [Google Scholar]
  13. Halperín J., Schaeffer R., Galvez L., Malavé S. Ouabain-like activity in human cerebrospinal fluid. Proc Natl Acad Sci U S A. 1983 Oct;80(19):6101–6104. doi: 10.1073/pnas.80.19.6101. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Joiner C. H., Lauf P. K. Modulation of ouabain binding and potassium pump fluxes by cellular sodium and potassium in human and sheep erythrocytes. J Physiol. 1978 Oct;283:177–196. doi: 10.1113/jphysiol.1978.sp012495. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Kaplan J. H. Sodium ions and the sodium pump: transport and enzymatic activity. Am J Physiol. 1983 Sep;245(3):G327–G333. doi: 10.1152/ajpgi.1983.245.3.G327. [DOI] [PubMed] [Google Scholar]
  16. Kelly R. A., O'Hara D. S., Canessa M. L., Mitch W. E., Smith T. W. Characterization of digitalis-like factors in human plasma. Interactions with NaK-ATPase and cross-reactivity with cardiac glycoside-specific antibodies. J Biol Chem. 1985 Sep 25;260(21):11396–11405. [PubMed] [Google Scholar]
  17. Lew V. L., Hardy M. A., Jr, Ellory J. C. The uncoupled extrusion of Na+ through the Na+ pump. Biochim Biophys Acta. 1973 Oct 11;323(2):251–266. doi: 10.1016/0005-2736(73)90149-1. [DOI] [PubMed] [Google Scholar]
  18. Pollack L. R., Tate E. H., Cook J. S. Na+, K+-ATPase in HeLa cells after prolonged growth in low K+ or ouabain. J Cell Physiol. 1981 Jan;106(1):85–97. doi: 10.1002/jcp.1041060110. [DOI] [PubMed] [Google Scholar]
  19. Sachs J. R. Sodium movements in the human red blood cell. J Gen Physiol. 1970 Sep;56(3):322–341. doi: 10.1085/jgp.56.3.322. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Sachs J. R., Welt L. G. The concentration dependence of active potassium transport in the human red blood cell. J Clin Invest. 1967 Jan;46(1):65–76. doi: 10.1172/JCI105512. [DOI] [PMC free article] [PubMed] [Google Scholar]
  21. Simons T. J. Potassium: potassium exchange catalysed by the sodium pump in human red cells. J Physiol. 1974 Feb;237(1):123–155. doi: 10.1113/jphysiol.1974.sp010474. [DOI] [PMC free article] [PubMed] [Google Scholar]
  22. Sugerman H. J., Pollock T. W., Rosato E. F., Delivoria-Papadopoulos M., Miller L. D., Oski F. A. Experimentally induced alterations in affinity of hemoglobin for oxygen. II. In vivo effect of inosine, pyruvate, and phosphate on oxygen-hemoglobin affinity in rhesus monkey. Blood. 1972 Apr;39(4):525–529. [PubMed] [Google Scholar]
  23. Tosteson D. C. Cation countertransport and cotransport in human red cells. Fed Proc. 1981 Apr;40(5):1429–1433. [PubMed] [Google Scholar]
  24. Wieth J. O. Paradoxical temperature dependence of sodium and potassium fluxes in human red cells. J Physiol. 1970 May;207(3):563–580. doi: 10.1113/jphysiol.1970.sp009081. [DOI] [PMC free article] [PubMed] [Google Scholar]