Transferrin

What is Transferrin?

Transferrin is a protein found in blood plasma and in milk. It is a glycoprotein of about 80 kilodalton in size, with two binding sites for iron. It binds to and transports iron around the body through the blood circulation, mainly to the bone marrow and spleen.

It is also transports iron from where it is stored in the liver to the brain and other tissues where it is needed for many cellular enzymatic reactions. Transferrin carries iron to the bone marrow where it drops it off to be assembled into hemoglobin molecules. Each transferrin molecule can carry two iron molecules at a time.

Blood transferrin levels are measured as a way to determine the cause of anemia, to check the iron-carrying capabilities of the blood and to examine the intricacies of iron metabolism. Excessive alcohol consumption affects transferrin, making it carbohydrate deficient and is therefore used as test for alcohol consumption.

The Functions of Transferrin

Maintains Cellular Iron Homeostasis

Transferrin carries iron throughout the body, helping cells regulate how much iron they absorb from the extracellular environment. Deficiencies in transferrin can lead to insufficient cellular iron, which inhibits cell growth. All cells have receptors for receiving iron from transferrin and these are necessary for proper cell functioning.

Inhibits Bacterial, Viral and Fungal Growth

Microorganisms need iron for their survival and growth. When a bacteria, virus or fungus infects the body it requires nutrients including iron in order to multiply quickly. By binding to iron, transferrin makes it unavailable to microorganisms, in theory. This deprivation makes microorganisms unable to thrive, minimizing the potential for infections. Therefore, it is hypothesized that transferrin is part of the body's immune system.

The Uses of Transferrin

A Cell Culture Media Additive

In cellular biology, transferrin is added to cell culture media to effectively increase the quality and quantity of cells by ensuring they are adequately supplied with iron. Additionally, its iron binding properties reduce the potential for damage to the cells caused by free radical molecules formed when iron chelators or other sources of iron are added to cell culture media.

Drug Delivery

Importance of Transferrin

Due to the importance of transferrin for cell culture and biomedicine, it is commonly isolated from both human and bovine sources. Human transferrin binds better to the human transferrin receptors, making iron transport more efficient and specific.

Unfortunately, there are safety concerns about infection and contamination with transferrin from human and bovine sources. There is also a shortage of commercially available human transferrin. Now, researchers use recombinant transferrin from animal-free sources.

Click here to find out more about Optiferrin^TM, the new animal-free, high-performance recombinant transferrin from InVitria.

References:

Burdo JR, James RC. (2003). Brain iron uptake and homeostatic mechanisms: An overview. Biometals: An International Journal on the Role of Metal Ions in Biology, Biochemistry and Medicine,16(1):63-75.

Cornelissen CN. (2008). Identification and characterization of gonococcal iron transport systems as potential vaccine antigens. Future Microbiology, 3:287-98.

Ganz, T. (2008). Iron homeostasis: Fitting the puzzle pieces together. Cell Metabolism, 7(4):288-90.

MacKenzie EL, Iwasaki K, Tsuji Y. (2008). Intracellular iron transport and storage: From molecular mechanisms to health implications. Antioxidants, 10(6):997-1030.

Sparling PF, Elkins C, Wyrick PB, Cohen MS. (1994). Vaccines for bacterial sexually transmitted infections: A realistic goal? Proceedings of the National Academy of Sciences of the United States of America, 91(7):2456-63.

Stafford JL, Belosevic M. (2003). Transferrin and the innate immune response of fish: identification of a novel mechanism of macrophage activation. Developmental and Comparative Immunology, 27(6-7):539-54.