In enzymology, a pyrogallol 1,2-oxygenase (EC 1.13.11.35) is an enzyme that catalyzes the chemical reaction

1,2,3-trihydroxybenzene + O₂ ${\displaystyle \rightleftharpoons }$ (Z)-5-oxohex-2-enedioate

Thus, the two substrates of this enzyme are 1,2,3-trihydroxybenzene and O₂, whereas its product is (Z)-5-oxohex-2-enedioate.

This enzyme belongs to the family of oxidoreductases, specifically those acting on single donors with O₂ as oxidant and incorporation of two atoms of oxygen into the substrate (oxygenases). The oxygen incorporated need not be derived from O₂. The systematic name of this enzyme class is 1,2,3-trihydroxybenzene:oxygen 1,2-oxidoreductase (decyclizing). This enzyme is also called pyrogallol 1,2-dioxygenase.