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