Individuals harboring a mutation in the aldolase B gene are subject to severe hypoglycemia upon consumption of fructose. The hypoglycemia can be explained by an impairment in glycogen phosphorylase-mediated glucose release from glycogen in response to glucagon. This metabolic defect can best be explained by which of the following?

Question

Quizplus · Accepted Answer

The accumulation of fructose 1-phosphate due to aldolase B deficiency depletes inorganic phosphate, which is necessary for glycogen phosphorylase activity, impairing glycogen breakdown and leading to hypoglycemia.  Glycogen phosphorylase carries out a phosphorolysis reaction on glycogen utilizing inorganic phosphate in the process of this reaction. Hypoglycemia after fructose ingestion is caused by accumulation of fructose 1-phosphate which simultaneously depletes inorganic phosphate pools, thereby inhibiting glycogenolysis at the level of glycogen phosphorylase which requires inorganic phosphate for activity.

Individuals Harboring a Mutation in the Aldolase B Gene Are