2,3-dihydroxyindole 2,3-dioxygenase () is an enzyme that catalyzes the chemical reaction
The two substrates of this enzyme are 2,3-dihydroxyindole and oxygen. Its two products are anthranilic acid and carbon dioxide.
This enzyme belongs to the family of oxidoreductases, specifically those acting on single donors with O<sub>2</sub> as oxidant and incorporation of two atoms of oxygen into the substrate (oxygenases). The oxygen incorporated need not be derived from O<sub>2</sub>. The systematic name of this enzyme class is 2,3-dihydroxyindole:oxygen 2,3-oxidoreductase (decyclizing). This enzyme participates in tryptophan metabolism.