What role do cofactors play in enzyme activity?

• A. They are involved in substrate breakdown
• B. They are organic compounds that provide energy
• C. They are inorganic metal ions that help substrates bind to enzymes
• D. They inhibit enzyme action

Answer: (C)

Cofactors are essential for the proper functioning of many enzymes, as they facilitate the binding of substrates to the enzyme itself. These cofactors are often inorganic metal ions, such as zinc, magnesium, or iron, which participate directly in the enzymatic reaction. They may help stabilize the enzyme-substrate complex or aid in the catalytic process by providing essential chemical groups that are necessary for the reaction to proceed efficiently. This interaction is crucial because without cofactors, many enzymes would be inactive, reducing the overall rate of biochemical reactions in the body.

In contrast, the other provided options highlight concepts that do not accurately describe the role of cofactors. While substrate breakdown is a function of enzymes, it is not directly related to the role of cofactors. Cofactors themselves do not provide energy; rather, they assist enzymes, which are the actual catalysts that drive these reactions. Additionally, cofactors do not inhibit enzyme action; instead, they enhance enzyme activity by enabling or improving the binding of the substrate to the enzyme, allowing the enzyme to fulfill its role in metabolism effectively.