Final answer:
Catechol oxidase requires a copper cofactor to function, enabling it to catalyze oxidation reactions involved in processes like the browning of produce.
Step-by-step explanation:
Catechol oxidase is an enzyme that requires a cofactor to function properly. This cofactor is usually a metal ion such as copper, which is integral to the enzyme's activity. Copper atoms attached to the enzyme's active site interact with oxygen to facilitate the oxidation reactions that catechol oxidase catalyzes. These reactions are essential for various biological processes, including the browning of fruits and vegetables upon exposure to air. Additionally, coenzymes like NAD+ may also play a role in assisting some oxidation reactions, although they are not specifically required by catechol oxidase.