Claim: Malate oxidase's oxidation activity can be restored by vitamin K, containing a functional naphthoquinone(an organic compound structurally related to naphthalene, the main ingredient for moth balls) ring.
Evidence: The addition of vitamin K, containing a functional naphthoquinone ring, restores the oxidation activity of malate oxidase. Naphthoquinone is a class of organic compounds structurally related to naphthalene. It is best known as the main ingredient of traditional mothballs.