Transferrin is described as which type of protein?

• A. An acute-phase reactant
• B. A beta-globulin that transports iron
• C. A lipoprotein
• D. An enzyme

Answer: (B)

Transferrin's primary role is to bind ferric iron in the bloodstream and transport it to cells via transferrin receptors. It is a secreted glycoprotein produced mainly by the liver and, on electrophoresis, resides in the beta-globulin region, which is why it’s described as a beta-globulin. This function as an iron carrier distinguishes it from lipoproteins or enzymes. While acute-phase behavior can occur, transferrin is typically considered a negative acute-phase reactant, meaning its levels often decrease during inflammation. So the description that it is a beta-globulin that transports iron best captures both its location and its function.