What is the allosteric site?

• A. site other than the active site
• B. Active site
• C. Cofactor binding site
• D. Substrate binding site

Answer: (A)

Allosteric regulation involves a regulatory site that is separate from the active site. When an effector molecule binds at this allosteric site, it causes a conformational change in the enzyme that alters the active site's shape or dynamics, increasing or decreasing its catalytic activity. So the allosteric site is defined by being away from the active site and serving a regulatory role. The active site is where the chemical reaction occurs, while substrate binding occurs at that active site; a cofactor binding site is for essential non-protein components, not the regulatory allosteric control.