Phosphofructokinase is the enzyme that is activated by ADP. This activation is a crucial part of cellular energy regulation.
How Phosphofructokinase is Activated by ADP
When ATP levels within a cell are low, ADP levels begin to rise. This accumulation of ADP acts as a signal to increase the rate of ATP production.
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Activation Mechanism: ADP directly binds to phosphofructokinase, a key enzyme in glycolysis. This binding enhances the enzyme's activity, allowing it to convert fructose-6-phosphate to fructose-1,6-bisphosphate at a higher rate.
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Glycolysis and ATP Production: Increased activity of phosphofructokinase drives the glycolytic pathway forward, leading to an increase in the production of ATP, the primary energy currency of the cell.
The Role of Phosphofructokinase in Glycolysis Regulation
Phosphofructokinase is a key regulatory point in glycolysis.
- Rate Limiting Step: It catalyzes one of the pathway's irreversible reactions, making it a major determinant of the overall flux through glycolysis.
- Feedback Regulation: In addition to ADP activation, phosphofructokinase is also inhibited by high levels of ATP and citrate, ensuring that glycolysis only proceeds when cellular energy demands require it.
Summary
| Enzyme | Activator | Pathway | Function |
|---|---|---|---|
| Phosphofructokinase | ADP | Glycolysis | Increases ATP production when cellular energy levels are low. |
In summary, when cellular ATP levels are depleted, ADP accumulates and this directly activates phosphofructokinase which increases the rate of glycolysis, generating more ATP.
