CeruloplasminĀ (orĀ caeruloplasmin) is aĀ ferroxidaseĀ enzymeĀ that in humans is encoded by theĀ CPĀ gene. Ceruloplasmin is the majorĀ copper-carrying protein in the blood, and in addition plays a role inĀ iron metabolism. It was first described in 1948. Another protein,Ā hephaestin, is noted for it