Which hormone regulates F2,6BP by decreasing its levels through phosphorylation of PFK-2?

Study for the Biochemistry Module 6 Exam. Study with flashcards and multiple choice questions; each question includes hints and explanations. Gear up to ace your test!

Multiple Choice

Which hormone regulates F2,6BP by decreasing its levels through phosphorylation of PFK-2?

The key idea is how hormones control the levels of fructose-2,6-bisphosphate (F2,6BP) by changing the activity of the PFK-2/FBPase-2 enzyme. In liver, glucagon raises cAMP and activates protein kinase A. This kinase phosphorylates the bifunctional enzyme, switching it toward FBPase-2 activity and away from PFK-2 activity. Since F2,6BP strongly stimulates PFK-1 and glycolysis, its levels fall when the enzyme is phosphorylated, so glycolysis slows and gluconeogenesis is favored. So glucagon lowers F2,6BP via phosphorylation of PFK-2, aligning with its role in promoting glucose production during fasting. Insulin would do the opposite by promoting dephosphorylation and increasing F2,6BP, boosting glycolysis. Epinephrine can trigger similar signaling, but the classic hepatic regulator of F2,6BP through PFK-2 phosphorylation is glucagon.

The key idea is how hormones control the levels of fructose-2,6-bisphosphate (F2,6BP) by changing the activity of the PFK-2/FBPase-2 enzyme. In liver, glucagon raises cAMP and activates protein kinase A. This kinase phosphorylates the bifunctional enzyme, switching it toward FBPase-2 activity and away from PFK-2 activity. Since F2,6BP strongly stimulates PFK-1 and glycolysis, its levels fall when the enzyme is phosphorylated, so glycolysis slows and gluconeogenesis is favored.

So glucagon lowers F2,6BP via phosphorylation of PFK-2, aligning with its role in promoting glucose production during fasting. Insulin would do the opposite by promoting dephosphorylation and increasing F2,6BP, boosting glycolysis. Epinephrine can trigger similar signaling, but the classic hepatic regulator of F2,6BP through PFK-2 phosphorylation is glucagon.

More practice questions