Which statement accurately describes the role of cofactors in enzymatic reactions?

Which statement accurately describes the role of cofactors in enzymatic reactions?

• A. They are non-protein molecules that help enzymes do reactions.
• B. They are a protein that helps enzymes.
• C. They are a type of substrate.
• D. They are a lipid that modifies enzyme.

Answer: (A)

Cofactors are non-protein components that assist enzymes in catalysis. They come in two main forms: inorganic metal ions like Mg2+, Zn2+, or Fe2+ that help stabilize transition states or orient substrates, and organic molecules called coenzymes (often derived from vitamins) such as NAD+ or FAD that participate directly in transferring electrons, hydrogens, or groups during the reaction. Some cofactors stay tightly bound as prosthetic groups, while others bind loosely and cycle on and off as the reaction proceeds. Without these helpers, many enzymes would be far less active or unable to function at all.

Cofactors are non-protein components that assist enzymes in catalysis. They come in two main forms: inorganic metal ions like Mg2+, Zn2+, or Fe2+ that help stabilize transition states or orient substrates, and organic molecules called coenzymes (often derived from vitamins) such as NAD+ or FAD that participate directly in transferring electrons, hydrogens, or groups during the reaction. Some cofactors stay tightly bound as prosthetic groups, while others bind loosely and cycle on and off as the reaction proceeds. Without these helpers, many enzymes would be far less active or unable to function at all.