Principles of Biochemistry, Volume 2 - A. Lehninger 1985
Bioenergetics and Metabolism
Biosynthesis of Carbohydrates in Animal Tissues
The third bypass pathway is the route leading from glucose-6-phosphate to free glucose.
The third and final bypass reaction in the synthesis of D-glucose is the dephosphorylation of glucose-6-phosphate to yield free glucose, which is released from the Liver into the bloodstream (Fig. 20-2). This dephosphorylation cannot proceed via the Reversal of the hexokinase reaction (Section 15.5,a), because that reaction is irreversible in the liver. Instead, the dephosphorylation of glucose-6-phosphate is mediated by glucose-6-phosphatase, which catalyzes the irreversible Hydrolysis reaction
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This Mg2+-dependent enzyme has a distinctive subcellular localization: it is found in the fraction of vertebrate liver Cells containing The Endoplasmic reticulum. Glucose-6-phosphatase is absent from Tissues such as Muscle or Brain, meaning they cannot supply free glucose to the Blood.
Last update: 06/08/2026
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