The key difference between ferritin and transferrin is that ferritin is a protein that stores iron in the blood whereas transferrin is a protein that can combine with ferritin and move to sites where new blood cells are formed.
Ferritin and transferrin are proteins that are important in storing and transporting iron in the blood. Ferritin can store iron that can be released under control. Transferrin is also involved in controlling the level of iron in biological fluids.
CONTENTS
1. Overview and Key Difference
2. What is Ferritin
3. What is Transferrin
4. Side by Side Comparison – Ferritin vs Transferrin in Tabular Form
5. Summary
What is Ferritin?
Ferritin is an intracellular protein that can store iron and release iron under control. Almost all living organisms can produce this protein, e.g. archaea, bacteria, plants, animals, etc. Furthermore, it can act as a buffer against iron deficiency in humans. In most of our tissues, this protein occurs as a cytosolic protein. Small amounts are secreted to the serum. In the serum, this protein can act as an iron carrier. Moreover, the level of ferritin in serum is also an indicator of the total amount of iron stored in our body. Generally, in vertebrates, the ferritin protein is present in cells. However, we can find a small amount in the plasma as well.
Figure 01: Nanocage of Ferritin
When considering its structure, ferritin is a globular protein. It contains 24 subunit proteins. Together, these subunits form a nanocage having multiple metal-protein interactions. Here, this nanocage can attract the iron metal and store it inside. With ferritin, iron exists in a soluble and non-toxic form. If the ferritin is not combined with iron, then we can name it as apoferritin.
Since ferritin stores iron in a non-toxic form (a safe form because free iron is toxic to cells), it can be directly transported to the required areas of the body. In different cell types, the function of ferritin may vary, which is controlled by the amount and stability of mRNA. More importantly, the amount of ferritin rapidly increases upon the presence of an infection or cancer. The concentration of ferritin increases upon stresses such as anoxia.
What is Transferrin?
Transferrin is a type of protein involved in the transport of ferritin. It is a type of iron-binding blood plasma glycoprotein. It can control the level of iron in biological fluids such as blood. In humans, transferrin is mainly produced in the liver, but some other organs such as the brain can also produce it in trace amounts. The binding of iron to transferrin is very tight but reversible. However, this protein is not specific for iron because it can bind with some other metals as well. The affinity of iron(III) to transferrin is very high. However, it decreases with decreasing the pH. If iron is not bound, we can name this protein as apotransferrin.
When considering the structure of transferrin, it has 679 amino acids along with two carbohydrate chains. And, this protein contains both the alpha-helix form and beta-sheet form. Moreover, transferrin contains an iron-bounder receptor. Furthermore, transferrin is associated with the innate immune system.
What is the Difference Between Ferritin and Transferrin?
Ferritin and transferrin are two important proteins in our blood. The key difference between ferritin and transferrin is that ferritin is a protein that stores iron in the blood whereas transferrin is a protein that can combine with ferritin and move to sites where new blood cells are formed.
Below infographic shows more comparisons related to the difference between ferritin and transferrin.
Summary – Ferritin vs Transferrin
Ferritin and transferrin are two important proteins in our blood that are useful to store and release iron under control. The key difference between ferritin and transferrin is that ferritin is a protein that stores iron in the blood whereas transferrin is a protein that can combine with ferritin and move to sites where new blood cells are formed.
Reference:
1. Bailey, Regina. “Proteins in the Cell.” ThoughtCo, Nov. 13, 2019, Available here.
Image Courtesy:
1. “Ferritin” (GPL) via Commons Wikimedia
2. “Protein TF PDB 1a8e” By Emw – Own work (CC BY-SA 3.0) via Commons Wikimedia