Promotes the biosynthesis of heme as well as the assembly and repair of iron-sulfur clusters by delivering Fe(2+) to proteins involved in these pathways. May play a role in the protection against iron-catalyzed oxidative stress through its ability to catalyze the oxidation of Fe(2+) to Fe(3+). May be able to store large amounts of the metal in the form of a ferrihydrite mineral by oligomerization. 4 Fe(2+) + 4 H(+) + O2 = 4 Fe(3+) + 2 H2O Monomer. Oligomer (By similarity). Belongs to the frataxin family.