FXN, also named as FRDA, X25, m81-FXN, d-FXN, m78-FXN and i-FXN, belongs to the frataxin family. It promotes the biosynthesis of heme and assembly and repair of iron-sulfur clusters by delivering Fe2+ to proteins involved in these pathways. FXN may play a role in the protection against iron-catalyzed oxidative stress through its ability to catalyze the oxidation of Fe2+ to Fe3+; the oligomeric form but not the monomeric form has in vitro ferroxidase activity. FXN is cleaved to be 4 chains. The mature form of FXN is 14kd or 18kd.
