Phosphofructokinase-1, the rate-limiting enzyme of glycolysis, is a classic allosterically regulated tetrameric enzyme. Which combination correctly lists its allosteric activators?
- A ATP and citrate
- B Fructose-6-phosphate and NADH
- C AMP and fructose-2,6-bisphosphate ✓
- D Citrate and long-chain fatty acyl-CoA
Correct answer: C. AMP and fructose-2,6-bisphosphate
Explanation
AMP signals a low-energy state and relieves ATP inhibition of PFK-1, while fructose-2,6-bisphosphate, produced by PFK-2 under insulin drive, is the most powerful physiologic activator, increasing the affinity for fructose-6-phosphate. ATP and citrate are inhibitors reflecting high energy and abundant biosynthetic precursors respectively, so option A lists inhibitors. Long-chain fatty acyl-CoA also inhibits PFK-1 in liver. Fructose-6-phosphate is the substrate, not an allosteric effector, and NADH signals reductive surplus rather than glycolytic need.
Reference: Lippincott Illustrated Reviews: Biochemistry, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.