In enzymology, a 3-hydroxyanthranilate oxidase (EC 1.10.3.5) (also called 3-HAO) is an enzyme that catalyzes the chemical reaction:(See Template:Leucine metabolism in humans – this diagram does not include the pathway for β-leucine synthesis via leucine 2,3-aminomutase) In enzymology, a 3-hydroxyanthranilate oxidase (EC 1.10.3.5) (also called 3-HAO) is an enzyme that catalyzes the chemical reaction: Thus, the two substrates of this enzyme are 3-hydroxyanthranilate and O2, whereas its two products are 6-imino-5-oxocyclohexa-1,3-dienecarboxylate and H2O2. This enzyme belongs to the family of oxidoreductases, specifically those acting on diphenols and related substances as donor with oxygen as acceptor. The systematic name of this enzyme class is 3-hydroxyanthranilate:oxygen oxidoreductase. This enzyme is also called 3-hydroxyanthranilic acid oxidase.