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. N-glycosylated on Trp by mannose. Belongs to the peroxidase family. XPO subfamily.