Intracellular free magnesium and phosphorylated metabolites in hexokinase- and pyruvate kinase-deficient red cells measured using 31P-NMR spectroscopy

Ronald Ouwerkerk, Cees J A van Echteld, Gerard E J Staal, Gert Rijksen

Research output: Contribution to journalArticlepeer-review

Abstract

The erythrocyte metabolism of two patients with nonspherocytic hemolytic anemia caused by a hexokinase deficiency, and a pyruvate kinase deficiency, respectively, were studied with NMR. The complexing of ATP and 2,3-diphosphoglycerate (2,3-DPG) with Mg2+ and hemoglobin (Hb) was determined using 31P-NMR on oxygenated and deoxygenated cells to investigate the influences of these enzyme defects on intracellular magnesium distribution and on Hb oxygen dissociation. In the pyruvate kinase-deficient red blood cells, the 2,3-DPG concentration was almost twice the normal value and the ATP concentration was near the lower limit of the normal range. In the hexokinase-deficient red cell population, the predominance of young cells masked the deficiency. Therefore, reticulocyte control cells were included in this study. In the oxygenated pyruvate kinase-deficient cells, the fraction of ATP that is complexed to magnesium as well as the free Mg2+ concentration were normal, despite the abnormal concentration of 2,3-DPG. In the deoxygenated cells, the free Mg2+ concentration was lower than in normal cells. The fraction of Hb complexed with 2,3-DPG was higher than normal in both oxygenated and deoxygenated pyruvate kinase-deficient cells, in accordance with the high p50 of the oxygen-hemoglobin dissociation curve. In hexokinase-deficient cells, two major abnormalities are found: when the cells were deoxygenated, the concentration of ATP and 2,3-DPG fell. This was not observed for any other sample and could, therefore, be a consequence of the hexokinase deficiency. Despite almost normal levels of magnesium-binding metabolites, the free Mg2+ concentration in oxygenated and deoxygenated cells is much lower than in normal cells. This could be a cell-age-related phenomenon, since lower free Mg2+ concentrations were also found in reticulocyte control cells.

Original languageEnglish (US)
Pages (from-to)294-303
Number of pages10
JournalBiochimica et Biophysica Acta - Molecular Cell Research
Volume1010
Issue number3
DOIs
StatePublished - Mar 6 1989
Externally publishedYes

Keywords

  • (Human red blood cell)
  • P-
  • Hexokinase deficiency
  • intracellular
  • Magnesium ion
  • NMR
  • Pyruvate kinase deficiency

ASJC Scopus subject areas

  • Biophysics
  • Cell Biology
  • Molecular Biology

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