Ceruloplasmin is predominantly synthesized by the cells of the liver parenchyma. This protein is an α2-globulin containing approximately 95% of the copper present in the serum. Each ceruloplasmin molecule contains between six and eight copper atoms. That is why it has long been thought that ceruloplasmin only served to transport this ion. However, it has been demonstrated that ceruloplasmin plays a major role in the regulation of the ionic state of iron: oxidizing ferrous iron to ferric iron at the cell surface, ceruloplasmin enables the incorporation of iron in transferrin without forming a toxic compound.
Ceruloplasmin is often assayed in evaluating for Wilson's disease, where the ceruloplasmin level is drastically low. Low levels of ceruloplasmin can also be detected in case of malnutrition or poor copper absorption.
Ceruloplasmin levels may increase during pregnancy or when taking oral contraceptives. Moreover, ceruloplasmin is a late protein of the inflammatory phase; its rate increases between four and twenty days after an inflammatory phase.