A competitive inhibitor is added to an enzyme-catalysed reaction. Which statement is correct?
Answer and explanation
Correct answer: A. The inhibitor binds to the active site, and a high substrate concentration can reduce its effect
- Step 1: A competitive inhibitor has a shape similar to the substrate and competes for the active site.
- Step 2: Adding more substrate makes it more likely that substrate binds, so the inhibition is reduced.
Answer
The inhibitor binds to the active site, and a high substrate concentration can reduce its effect.
Why not the others: The inhibitor binds away from the active site and changes the shape of the enzyme: describes a non-competitive inhibitor. The inhibitor permanently denatures the enzyme so more substrate has no effect: competitive inhibition is reversible and can be overcome. The inhibitor increases the activation energy of the substrate only: the inhibitor works by blocking the active site.
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