Feedback Inhibition

In a regulatory process called feedback inhibition, the product of a reaction inhibits an enzyme at an earlier step in the metabolic pathway that produced it, thereby slowing, or shutting down, its own production.

The product does this by binding to a regulatory site on the enzyme, which is distinct from the active site that binds to the substrate. When the product binds to regulatory site, it causes a confirmational change in the enzyme that inhibits it from continuing to catalyze the reaction.

This activity prevents excessively high levels of the product from accumulating, and, once the level drops low enough, the product no longer inhibits the enzyme, and production can continue as usual.