How does allosteric inhibition change enzyme activity?

Allosteric inhibition regulates enzyme activity by utilizing a specific regulatory site, known as an allosteric site, which is distinct from the enzyme's active site.12

When an allosteric inhibitor binds to this regulatory site, it induces a conformational change in the shape of the enzyme. This structural alteration affects the enzyme's active site in one of two primary ways:32

• Distortion of the active site: The change in shape may prevent the enzyme from effectively binding its substrate, as the essential binding groups are no longer properly oriented.2
• Catalytic misalignment: In cases of noncompetitive inhibition, the inhibitor may not prevent the substrate from binding, but it distorts the active site such that the catalytic groups are misaligned, rendering the enzyme unable to convert the substrate into a product.2

Because this process is reversible—the enzyme returns to its original shape once the inhibitor dissociates—allosteric control functions as a flexible, thermostat-like system that allows the cell to coordinate metabolic pathways and maintain homeostasis.32