Na+,K+-ATPase of human placenta during gestational hypertension: A biochemical-biophysical study

Rosa A. Rabini, Giovanna Zolese, Roberto Staffolani, G. Lucarelli, E. Amler, Nelvio Cester, Laura Mazzanti

Research output: Contribution to journalArticle

Abstract

1. Na+,K+-ATPase is the membrane enzyme catalysing the active transport of Na+ and KC across the plasma membrane of animal cells. A reduced activity of Na+,K+-ATPase has been described in gestational hypertension in a variety of cell types, in agreement, with the hypothesis that gestational hypertension can induce membrane transport modifications similar to those reported for essential hypertension. The causes of the reduced Na+,K+-ATPase activity are still debated. 2. The aim of the present work was to investigate the molecular mechanism of the reduced enzymic activity in gestational hypertension using as a model Na+,K+-ATPase purified from human placenta, Na+,K+-ATPase obtained from term placentas of eight healthy pregnant women and eight age-matched women with gestational hypertension was purified as previously described. 3. We observed in gestational hypertension: (i) a significant increase in the activation energies above transition temperature; (ii) a significant decrease in the fluorescence polarization of 1-(4-trimethylaminophenyl)-6-phenyl-1,3,5-hexatriene (i.e. increased fluidity) and an increase in the mean lifetime (modified hydrophobicity); (iii) a lower K(q), suggesting an enzymic structural modification; and (iv) an increased mean lifetime and rotational relaxation time of pyrene isothiocyanate, indicating a modified ATB binding site.

Original languageEnglish
Pages (from-to)719-723
Number of pages5
JournalClinical Science
Volume91
Issue number6
Publication statusPublished - 1996

Keywords

  • Activation energy
  • Fluidity
  • Gestational hypertension
  • K-ATpase
  • Na
  • Placenta
  • Tryptophan

ASJC Scopus subject areas

  • Medicine(all)

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    Rabini, R. A., Zolese, G., Staffolani, R., Lucarelli, G., Amler, E., Cester, N., & Mazzanti, L. (1996). Na+,K+-ATPase of human placenta during gestational hypertension: A biochemical-biophysical study. Clinical Science, 91(6), 719-723.