Ferritin is one of the major non-heme iron storage proteins in animals, plants and microorganisms [<cite idref="PUB00001349"/>, <cite idref="PUB00000049"/>]. It consists of a mineral core of hydrated ferric oxide, and a multi-subunit protein shell which encloses the former and assures its solubility in an aqueous environment. <p> In animals, the protein is mainly cytoplasmic and there are generally two or more genes that encode closely related subunits (in mammals there are two subunits which are known as H(eavy) and L(ight)). In plants ferritin is found in the chloroplast [<cite idref="PUB00002586"/>].</p><p>This entry represents the central region of this protein.</p> Ferritin, conserved site