Ferritin Heavy Chain Products

Stores iron in a soluble. nontoxic. readily available form. Important for iron homeostasis. Has ferroxidase activity. Iron is taken up in the ferrous form and deposited as ferric hydroxides after oxidation. Ferritin is a ubiquitous and highly conserved protein which plays a major role in iron homeostasis by sequestering and storing iron in a non-toxic and soluble form. It forms a holoenzyme of ~450 kDa, consisting of 24 subunits of two types, H (heavy; 21 kDa) and L (light; 19 kDa), and is capable of storing up to 4,500 atoms of ferric iron. Depending on the tissue type and physiological status of the cell, the ratio of H to L subunits in ferritin can vary widely. Ferritin is found in the liver, spleen, kidney and heart, with smaller amounts being found in blood. Serum ferritin levels serve as an indicator of the amount of iron stored in the body. Serum ferritin is the most sensitive test for anaemia, and is also used as a marker for restless leg syndrome, hemochromatosis and porphyria. As ferritin is an acute-phase reactant, it is often elevated during infection. Defects in ferritin proteins are associated with several neurodegenerative diseases.