In enzymology, a pteridine oxidase (EC 1.17.3.1) is an enzyme that catalyzes the chemical reaction

2-amino-4-hydroxypteridine + O₂ 2-amino-4,7-dihydroxypteridine + (?)

Thus, the two substrates of this enzyme are 2-amino-4-hydroxypteridine and O₂, whereas its product is 2-amino-4,7-dihydroxypteridine.

This enzyme belongs to the family of oxidoreductases, specifically those acting on CH or CH₂ groups with oxygen as acceptor. The systematic name of this enzyme class is 2-amino-4-hydroxypteridine:oxygen oxidoreductase (7-hydroxylating).

• Yong YN (1980). "Detection of a pteridine oxidase in plants". Plant Sci. Lett. 18: 169–175. doi:10.1016/0304-4211(80)90047-4.