Competitive Inhibition Properties

Steps:

• Identify key traits: competitive inhibitors bind reversibly to the enzyme's active site, competing with substrate.
• Recall Lineweaver-Burk effects: they increase Km (apparent affinity decreases) but Vmax stays the same at saturating substrate levels.
• Evaluate statements: 1 (binds active site) and 3 (increases Km) align with definition; 2 (decreases Vmax) and 4 (irreversible binding) do not.
• Select option listing only correct statements: B covers 1 and 3.

Why B is correct:

• Competitive inhibitors raise Km by competing for the active site but do not alter Vmax, per Michaelis-Menten kinetics.

Why the others are wrong:

• A includes 2, which falsely lowers Vmax (non-competitive trait).
• C omits 3, ignoring Km increase.
• D includes 2 and 4, both incorrect (Vmax unchanged; binding reversible).

Final answer: B