May function as a ferroxidase for ferrous (II) to ferric ion (III) conversion and may be involved in copper transport and homeostasis. Implicated in iron homeostasis and may mediate iron efflux associated to ferroportin 1. Binds 6 Cu cations per monomer. Defects in Heph are a cause of the sex-linked anemia (sla) that is characterized by moderate to severe microcytic hypochronic anemia. Belongs to the multicopper oxidase family.