In allosteric regulation, which molecules modify the rate of enzyme activity by binding at a site other than the active site?

• A. Allosteric effectors (activators or inhibitors)
• B. Competitive inhibitors
• C. Covalent modifiers that irreversibly inactivate the active site
• D. Substrates that bind only at the active site

Answer: (A)

Verified step by step guidance

1. Understand that allosteric regulation involves molecules binding to an enzyme at a site distinct from the active site, which influences the enzyme's activity.
2. Identify that molecules binding at the active site are typically substrates or competitive inhibitors, which directly compete with the substrate.
3. Recognize that covalent modifiers irreversibly alter the enzyme, often at the active site, and are not reversible allosteric regulators.
4. Define allosteric effectors as molecules (either activators or inhibitors) that bind to allosteric sites, causing conformational changes that modify enzyme activity.
5. Conclude that the molecules modifying enzyme activity by binding at a site other than the active site are allosteric effectors.