Hydrolysis of ATP
Biology: AQA A Level, topic 1.6.2
Hydrolysis of ATP
Hydrolysis of ATP happens when a cell needs energy.
ATP hydrolysis reaction
- The equation for the hydrolysis of ATP is:
- ATP + H2O → ADP + Pi (+ energy)
- Hydrolysis of ATP to adenosine diphosphate (ADP) and an inorganic phosphate group (Pi) is catalysed by the enzyme ATP hydrolase.
- This reaction uses a water molecule so is called a hydrolysis reaction.
Energy release
- Energy is released during the hydrolysis of ATP as one of the phosphate bonds is broken.
- This energy is used to perform work inside the cell.
Energy coupling
- The hydrolysis of ATP can be coupled to other reactions within cells that need energy.
- An example of energy coupling using ATP is the transmembrane sodium-potassium pump (Na+/K+ pump):
- Energy is released from the hydrolysis of ATP.
- Energy is needed to power the pump that drives Na+ out of the cell and K+ into the cell.
Phosphorylation
- The inorganic phosphate released in ATP hydrolysis can be used to phosphorylate other compounds.
- This often makes the compounds more reactive.
Test yourself on Hydrolysis of ATP
Which enzyme catalyses ATP hydrolysis?
How does ATP's inorganic phosphate make other compounds more reactive?