[Campbell Biology P.233] Which of the following correctly describes the allosteric regulatio... | Practice Question

Which of the following correctly describes the allosteric regulation of phosphofructokinase PFK , the pacemaker enzyme of glycolysis?

  • A: ATP stimulates PFK activity, while AMP inhibits it.
  • B: Citrate stimulates PFK activity, leading to increased glycolysis.
  • C: High levels of ATP inhibit PFK, while high levels of AMP activate it.
  • D: PFK is only regulated by substrate concentration, not by allosteric effectors.

Explanation

Phosphofructokinase PFK is an allosteric enzyme. High levels of ATP indicating ample energy inhibit PFK, slowing down glycolysis. Conversely, high levels of AMP indicating low energy activate PFK, accelerating glycolysis. Citrate, a product of the citric acid cycle, also inhibits PFK, synchronizing the rates of glycolysis and the citric acid cycle.