How do competitive inhibitors affect enzyme activity?

Competitive inhibitors affect enzyme activity by binding to the active site of the enzyme. This mimics the structure of the substrate and competes with it for the active site, thereby preventing the substrate from binding and subsequently inhibiting the enzyme's ability to catalyze the reaction. Because they occupy the same site as the substrate, an increase in substrate concentration can overcome the effect of competitive inhibitors, thereby allowing the reaction to proceed if there is enough substrate available.

The unique characteristic of competitive inhibition is that it does not permanently alter the enzyme's structure or function; rather, it temporarily blocks access to the active site. This allows the enzyme to return to its normal activity if the inhibitor is removed or if the substrate concentration exceeds that of the inhibitor. Understanding this mechanism is critical for grasping how certain drugs and chemicals can regulate metabolic pathways by acting as competitive inhibitors.