Glycolysis and gluconeogenesis: A teaching view

Open AccessPublished:December 07, 2020DOI:
      I read with interest the recent review “Tracking the carbons supplying gluconeogenesis” by Ankit M. Shah and Fredric E. Wondisford (
      • Shah A.M.
      • Wondisford F.E.
      Tracking the carbons supplying gluconeogenesis.
      ). The figures are clear, and they are a good teaching source. Nevertheless, I note some potential teaching issues as well as offer additional suggestions. It is well known and it is explained to our students that there are three reactions of glycolysis that are essentially irreversible: hexokinase, phosphofrutokinase-1, and pyruvate kinase. Thus, I would like to observe in relation to Figure 1 that
      • (1)
        With the first two reactions as from glucose to glucose-6-phosphate and from fructose-6-phosphate to fructose-1,6-bisphosphate, the enzymes in both directions should be labeled;
      • (2)
        With the reaction from phosphoenolpyruvate to pyruvate, there should be one single arrow;
      • (3)
        There should be another single arrow between pyruvate and oxaloacetate.

      Conflict of interest

      The authors declare that they have no conflicts of interest with the contents of this article.


        • Shah A.M.
        • Wondisford F.E.
        Tracking the carbons supplying gluconeogenesis.
        J. Biol. Chem. 2020; 295: 14419-14429

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      • Reply to Hernández—Glycolysis and gluconeogenesis: A teaching view
        Journal of Biological ChemistryVol. 296
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          We thank Félix Hernández for his insightful and thoughtful comments as well as interest in our manuscript (1). Regarding suggestion 1, we omitted several glycolytic and gluconeogenic enzymes in the figure for simplicity. We specifically mentioned G6Pase and PEPCK as many investigators have studied these enzymes in particular when studying gluconeogenesis. Articles specifically referenced in our review article studied these two enzymes, and we wished to pictorially represent these enzymes. We further described each of these two enzymes’ specific functions in the text.
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