Which protein binds the majority of copper in the blood?

Which protein binds the majority of copper in the blood?

• A. Transferrin
• B. Ceruloplasmin
• C. Albumin
• D. Cryoglobulin

Answer: (B)

Copper in the blood is carried primarily by a specific plasma protein called ceruloplasmin. This protein binds multiple copper ions per molecule and serves as the main transporter of copper in circulation. Because of this, the majority of circulating copper is bound to ceruloplasmin rather than to other proteins. Transferrin is the main transporter of iron, not copper. Albumin does bind many small molecules in plasma but is not the primary copper carrier. Cryoglobulins are immunoglobulins that precipitate in cold temperatures and have no role in copper transport. Ceruloplasmin also has ferroxidase activity, linking copper transport to iron metabolism, which helps illustrate why this protein is central to copper handling in the blood.

Copper in the blood is carried primarily by a specific plasma protein called ceruloplasmin. This protein binds multiple copper ions per molecule and serves as the main transporter of copper in circulation. Because of this, the majority of circulating copper is bound to ceruloplasmin rather than to other proteins.

Transferrin is the main transporter of iron, not copper. Albumin does bind many small molecules in plasma but is not the primary copper carrier. Cryoglobulins are immunoglobulins that precipitate in cold temperatures and have no role in copper transport. Ceruloplasmin also has ferroxidase activity, linking copper transport to iron metabolism, which helps illustrate why this protein is central to copper handling in the blood.