Required for ovarian follicle maturation. Involved in the formation of a rigid and insoluble egg chorion by catalyzing chorion protein cross-linking through dityrosine formation and phenol oxidase-catalyzed chorion melanization. 2 a phenolic donor + H2O2 = 2 a phenolic radical donor + 2 H2O Binds 1 heme b (iron(II)-protoporphyrin IX) group per heterodimer. Heterodimer. In the chorion layer of the mature eggs. Expressed at low levels in the germarium and early follicles. Expression becomes progressively stronger during vitellogenesis, and is highly expressed in germ cells and somatic cells. A subset of follicle cells, termed border cells (BC), exhibit a high level of expression. Expressed both maternally and zygotically. Females are sterile, and maturing follicles show defects in actin filament formation, nurse cell membrane stability and border cell migration. Belongs to the peroxidase family. XPO subfamily. Extended C-terminus.