Ferric cation

Iron is incorporated into various proteins to serve biological functions as a structural component or cofactor. Once ferric or ferrous cation from intestinal enterocytes or reticuloendothelial macrophages is bound to circulating transferrin, iron-transferrin complex binds to the cell-surface transferrin receptor (TfR) 1, resulting in endocytosis and uptake of the metal cargo. Internalized iron is transported to mitochondria for the synthesis of heme or iron-sulfur clusters, which are integral parts of several metalloproteins. Excess iron is stored and detoxified in cytosolic ferritin. Internalized Fe2+ exported across the basolateral membrane into the bloodstream via Fe+2 transporter ferroportin, which is coupled by reoxidation to Fe3+ via membrane-bound ferroxidase hephaestin or ceruloplasmin activity. Fe+3 is again scavenged by transferrin which maintains the ferric iron in a redox-inert state and delivers it into tissues.

Fe3+ participates in the autoxidation reaction, where it can be chelated by DNA. It mainly binds to the backbone phosphate group, whereas at higher metal ion content, the cation binds to both guanine N-7 atom and the backbone phosphate group.