What inhibits PFK-1 in the glycolytic pathway?

Phosphofructokinase-1 (PFK-1) is a key regulatory enzyme in the glycolytic pathway, largely responsible for converting fructose-6-phosphate to fructose-1,6-bisphosphate using ATP. The regulation of PFK-1 is crucial for controlling the rate of glycolysis based on the cell's energy needs.

ATP serves as an allosteric inhibitor of PFK-1. When cellular ATP levels are high, it signals that there is sufficient energy available, leading to the inhibition of PFK-1. Conversely, when ATP levels are low, ADP levels increase, which serves as a signal to activate PFK-1, promoting glycolysis to generate more ATP.

Citrate, an intermediate of the citric acid cycle, indicates that there is an abundance of energy and building blocks available for biosynthesis. High citrate levels will also inhibit PFK-1, further signaling that glycolysis should decrease since there is no immediate need for further ATP production.

Both ATP and citrate serve as potent inhibitors of PFK-1, which means when the cell has an adequate energy supply or essential biosynthetic precursors, the activity of glycolysis is downregulated.

In this context, the role