Ferritin is a globular protein found mainly in the liver, which can store about 4500 iron ions in a hollow shell made of 24 identical subunits. Inside the ferritin shell, iron ions form crystallites together with phosphate and hydroxide ions.
Ferritin without iron is called apoferritin. Apoferritin combines with iron making ferritin.
Some ferritin complexes in vertebrates are hetero-oligomers of two highly-related gene products with slightly different physiological properties. The ratio of the two homologous proteins in the complex depends on the relative expression levels of the two genes.
Uses
Serum ferritin levels are measured in patients as part of the iron studies workup for anemia. The ferritin levels measured have a direct correlation with the total amount of iron stored in the body. If Ferritin is high there is iron in excess, which would be excreted in the stool. If ferritin is low there is a risk for lack in iron which sooner or later could lead to anaemia.
Ferritin is also used as a marker for iron overload disorders, such as haemochromatosis and porphyria in which the ferritin level may be abnormally raised.
As ferritin is also an acute-phase reactant, it is often elevated in the course of disease. A normal C-reactive protein can be used to exclude elevated ferritin caused by acute phase reactions.
The content of this page is retrieved from http://en.wikipedia.org/wiki/Ferritin under GFDL
