Competitive Inhibition Reversibility

Steps:

• Recall that competitive inhibitors bind to the enzyme's active site, competing with the substrate.
• Understand that this binding is reversible and non-covalent, allowing substrate to displace the inhibitor.
• Evaluate options: A suggests permanent binding (non-competitive trait), B matches reversibility by substrate increase, C involves structural changes (allosteric), D confuses shapes.
• Confirm B aligns with Michaelis-Menten kinetics, where Km increases but Vmax stays constant.

Why B is correct:

• In competitive inhibition, increasing substrate concentration overcomes inhibition by outcompeting the inhibitor for the active site, as defined in enzyme kinetics.

Why the others are wrong:

• A: Competitive inhibition is reversible, not permanent; permanent binding is irreversible inhibition.
• C: Competitive inhibitors do not alter secondary structure; they mimic substrate shape without changing enzyme conformation.
• D: Substrates fit the active site, but inhibitors compete by similar shape; enzymes do not share shape with both.

Final answer: B