Answer:
The answer is fructose 2,6-bisphosphate
Step-by-step explanation:
Phosphofructokinase is activated by a high concentration of AMP, but the most potent activator is fructose 2,6-bisphosphate, which is also produced from fructose-6-phosphate by PFK2.
Fructose 2,6-bisphosphate activates phosphofructokinase by increasing its inclination towards fructose 6-phosphate and reducing the inhibitory effect of ATP. In essence, Fructose 2,6-bisphosphate is an allosteric activator that shifts the conformational equilibrium of this enzyme from the T state to the R state.