Ferritin(redirected from ferritins)
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a complex protein (metalloprotein) in which iron is stored in humans and animals. Ferritin is present in the liver, spleen, and bone marrow and in the mucous membrane of the intestines. It was discovered in 1934 by the Czechoslovak scientist Laufberger, who detected the protein in the liver of animals.
Ferritin is the most iron-rich compound in organisms, with approximately one atom of trivalent iron for each amino acid residue of protein. In contrast to hemoproteins, the iron in ferritin is not part of the heme, occurring instead in a complex with the inorganic polymeric compound (FeO·OH)18(FeO·OPO3H2), which is firmly bound to the protein. The molecular weight of ferritin is 747,000; with detachment of the iron, apoferritin is formed, which has a molecular weight of 465,000.
Ferritin exhibits antigenic properties. The ferritin in the mucous membrane of the intestines regulates the absorption of iron and the entrance of iron into the blood. The release of Fe occurs through the action of a reducing agent, in this case ascorbic acid (vitamin C). The iron entering the blood is carried by transferrin to the liver and other organs, where any excess combines with apoferritin. The Fe entering into the composition of ferritin is necessary for the synthesis of hemoglobin, cytochromes, and other iron-containing compounds. An increased need for iron in the body causes a rapid decomposition of ferritin in bone marrow, the liver, and the spleen.
N. N. CHERNOV