Which glycolytic enzyme is highly regulated by ATP, AMP, and fructose-2,6-bisphosphate?

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Multiple Choice

Which glycolytic enzyme is highly regulated by ATP, AMP, and fructose-2,6-bisphosphate?

Glycolysis is regulated at the committed, rate-limiting step by an enzyme that responds to the cell’s energy status. Phosphofructokinase-1 catalyzes the conversion of fructose-6-phosphate to fructose-1,6-bisphosphate and sits at the key control point. It is inhibited by high ATP, which signals plenty of energy, and activated by AMP, which indicates low energy. Fructose-2,6-bisphosphate is a powerful activator of this enzyme, produced in response to insulin via PFK-2, and it can greatly boost PFK-1 activity even when ATP levels are relatively high. This combination makes PFK-1 the enzyme most closely regulated by ATP, AMP, and fructose-2,6-bisphosphate, integrating energy status and hormonal signals to modulate glycolytic flux. Other enzymes in glycolysis are regulated differently—for example, hexokinase is mainly controlled by its product G6P, and pyruvate kinase has its own separate regulatory signals—so the central, dominant integration by these metabolites points to phosphofructokinase-1.

Glycolysis is regulated at the committed, rate-limiting step by an enzyme that responds to the cell’s energy status. Phosphofructokinase-1 catalyzes the conversion of fructose-6-phosphate to fructose-1,6-bisphosphate and sits at the key control point. It is inhibited by high ATP, which signals plenty of energy, and activated by AMP, which indicates low energy. Fructose-2,6-bisphosphate is a powerful activator of this enzyme, produced in response to insulin via PFK-2, and it can greatly boost PFK-1 activity even when ATP levels are relatively high. This combination makes PFK-1 the enzyme most closely regulated by ATP, AMP, and fructose-2,6-bisphosphate, integrating energy status and hormonal signals to modulate glycolytic flux. Other enzymes in glycolysis are regulated differently—for example, hexokinase is mainly controlled by its product G6P, and pyruvate kinase has its own separate regulatory signals—so the central, dominant integration by these metabolites points to phosphofructokinase-1.

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