2,5-dihydroxypyridine 5,6-dioxygenase () is an enzyme that catalyzes the chemical reaction
The two substrates of this enzyme are 2,5-dihydroxypyridine and oxygen. Its product is N-formylmaleamic acid.
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>. It employs one cofactor, iron.
This enzyme participates in nicotinate and nicotinamide metabolism.
The systematic name of this enzyme class is 2,5-dihydroxypyridine:oxygen 5,6-oxidoreductase. Other names in common use include 2,5-dihydroxypyridine oxygenase, and pyridine-2,5-diol dioxygenase.