Iron is the most abundant element on earth representing nearly 90% of the mass in the earth’s core, yet only trace elements are present in living cells. Most of the iron in the body is located within the porphyrin ring of heme, which is incorporated into proteins such as hemoglobin, myoglobin, cytochromes, catalases and peroxidases. Although iron appears in a variety of oxidation states, in particular as hexavalent ferrate, the ferrous and ferric forms are of most importance. The transition from ferrous to ferric iron and vice versa occurs readily, meaning that Fe(II) acts as a reducing agent and Fe(III) as an oxidant. Iron is closely involved.
