Transferrin

Transferrin is a glycoprotein that binds and transports iron ions in the blood. It is primarily synthesized in the liver and plays a crucial role in the regulation of iron absorption and distribution in the body.

Structure

Transferrin is a single-chain glycoprotein with a molecular weight of approximately 80 kDa. It consists of two lobes, each capable of binding one iron ion. The protein undergoes a conformational change upon iron binding, which is essential for its function in iron transport.

Structure of transferrin with bound iron ion.

Function

The primary function of transferrin is to transport iron from sites of absorption and storage to sites of utilization. Iron is absorbed in the duodenum and binds to transferrin in the plasma. Transferrin then delivers iron to cells by binding to transferrin receptors on the cell surface, facilitating iron uptake through receptor-mediated endocytosis.

Iron Homeostasis

Transferrin plays a critical role in maintaining iron homeostasis. It regulates the level of free iron in the blood, preventing iron-mediated oxidative damage. The transferrin saturation level is an important clinical marker for assessing iron status in the body.

Blood values sorted by mass and molar concentration, including transferrin.

Clinical Significance

Abnormal levels of transferrin can indicate various medical conditions. Low transferrin levels may be associated with iron deficiency anemia, while high levels can be indicative of iron overload disorders such as hemochromatosis. Transferrin levels are also used to calculate the transferrin saturation index, which helps in diagnosing iron-related disorders.

Research and Applications

Transferrin is used in various research applications, including studies on iron metabolism and drug delivery systems. Its ability to bind and transport iron makes it a target for therapeutic interventions in diseases related to iron metabolism.

Another view of the transferrin structure.

Related pages

• Iron metabolism
• Hemochromatosis
• Anemia
• Transferrin receptor

References

• Aisen, P., Enns, C., & Wessling-Resnick, M. (2001). Chemistry and biology of eukaryotic iron metabolism. International Journal of Biochemistry & Cell Biology, 33(10), 940-959.
• Hentze, M. W., Muckenthaler, M. U., & Andrews, N. C. (2004). Balancing acts: molecular control of mammalian iron metabolism. Cell, 117(3), 285-297.

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  Transferrin structure 1
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  Transferrin structure 2
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  Blood values sorted by mass and molar concentration