In enzymology, a pteridine oxidase () is an enzyme that catalyzes the chemical reaction
Thus, the two substrates of this enzyme are 2-amino-4-hydroxypteridine and O<sub>2</sub>, whereas its product is 2-amino-4,7-dihydroxypteridine.
This enzyme belongs to the family of oxidoreductases, specifically those acting on CH or CH<sub>2</sub> groups with oxygen as acceptor. The systematic name of this enzyme class is 2-amino-4-hydroxypteridine:oxygen oxidoreductase (7-hydroxylating).