90% of the copper present in the blood is bound to which protein?

90% of the copper present in the blood is bound to which protein?

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

Answer: (B)

Copper in plasma is carried mainly by ceruloplasmin, a copper-containing enzyme produced by the liver. About 90% (often cited in the 70–95% range) of circulating copper is bound to ceruloplasmin, making it the primary transport form. The remaining copper is mostly bound to albumin and other small molecules, while transferrin ferries iron, not copper. Cryoglobulin is unrelated to copper transport. This is why ceruloplasmin is the correct choice.

Copper in plasma is carried mainly by ceruloplasmin, a copper-containing enzyme produced by the liver. About 90% (often cited in the 70–95% range) of circulating copper is bound to ceruloplasmin, making it the primary transport form. The remaining copper is mostly bound to albumin and other small molecules, while transferrin ferries iron, not copper. Cryoglobulin is unrelated to copper transport. This is why ceruloplasmin is the correct choice.