part_of iron homeostasis pathway iron storage pathway PW:0000592 The main storage system for iron is represented by ferritin. The iron entering the cell is in its ferrous Fe(II) form. It is oxidized to the stored ferric Fe(III) by the oxidase activity of ferritin heavy chain. Neuromelanin pigment, abundant in the dopaminergic neurons of the substantia nigra, is known as a metal chelator and is the storage form of iron in these cells. pathway