D-mannoheptulose phosphorylation by hexokinase isoenzymes

  • Authors:
    • P. Courtois
    • A. Sener
    • W. J. Malaisse
  • View Affiliations

  • Published online on: April 1, 2001     https://doi.org/10.3892/ijmm.7.4.359
  • Pages: 359-363
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Abstract

D-mannoheptulose is a specific inhibitor of D-glucose phosphorylation by hexokinase isoenzymes. In the present study, the phosphorylation of this heptose was investigated by either a spectrophotometric or radioisotopic procedure. Using yeast hexokinase, the phosphorylation of 25 mM D-mannoheptulose only represented 0.02% of that of 5 mM D-glucose. Such a percentage was increased to 3.93% in the case of bovine heart hexokinase. In the latter case, the Km for D-mannoheptulose was close to 0.2 mM and both D-glucose (0.1-1.0 mM) and D-glucose 6-phosphate (also 0.1-1.0 mM) inhibited the phosphorylation of the heptose (0.03-0.60 mM). Human B-cell glucokinase also catalyzed the phosphorylation of D-mannoheptulose (0.1 mM), which was now increased in a bell-shaped manner by D-glucose (1.0-20 mM). Likewise, rat parotid gland, liver and pancreatic islet homogenates catalyzed the phosphorylation of D-[3H]mannoheptulose. The results obtained in these three tissues differed from one another by their absolute values (per mg wet wt.), relative values (by reference to the phosphorylation rate of 10 mM D-glucose), and sensitivity to inhibition by D-glucose (10 mM).

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April 2001
Volume 7 Issue 4

Print ISSN: 1107-3756
Online ISSN:1791-244X

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Spandidos Publications style
Courtois P, Sener A and Malaisse WJ: D-mannoheptulose phosphorylation by hexokinase isoenzymes. Int J Mol Med 7: 359-363, 2001.
APA
Courtois, P., Sener, A., & Malaisse, W.J. (2001). D-mannoheptulose phosphorylation by hexokinase isoenzymes. International Journal of Molecular Medicine, 7, 359-363. https://doi.org/10.3892/ijmm.7.4.359
MLA
Courtois, P., Sener, A., Malaisse, W. J."D-mannoheptulose phosphorylation by hexokinase isoenzymes". International Journal of Molecular Medicine 7.4 (2001): 359-363.
Chicago
Courtois, P., Sener, A., Malaisse, W. J."D-mannoheptulose phosphorylation by hexokinase isoenzymes". International Journal of Molecular Medicine 7, no. 4 (2001): 359-363. https://doi.org/10.3892/ijmm.7.4.359