What type of enzyme inhibition involves binding directly to the active site?

Inhibition of enzymes can occur through various mechanisms, and competitive inhibition specifically involves the direct binding of an inhibitor to the active site of the enzyme. This competition prevents the substrate from binding effectively. As both the substrate and the inhibitor vie for the same active site, increasing concentrations of substrate can overcome this type of inhibition, allowing normal enzymatic activity to resume.

In contrast, non-competitive inhibition occurs when an inhibitor binds to an allosteric site, altering the enzyme's shape and function without competing with the substrate for the active site. Allosteric inhibition also involves binding at a site other than the active site, leading to a change in the enzyme’s configuration. Feedback inhibition is a regulatory mechanism where the end product of a metabolic pathway inhibits an upstream process, often occurring via allosteric sites rather than the active site.

Thus, the defining characteristic of competitive inhibition is that the inhibitor directly competes with the substrate for the active site, which effectively reduces enzyme activity until a sufficient amount of substrate is present to displace the inhibitor.