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 (PubMed:17092311). 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+) (PubMed:17092311). May be able to store large amounts of the metal in the form of a ferrihydrite mineral by oligomerization (PubMed:17092311). Binds to the mitochondrial cysteine desulfurase NIFS1 and increases its activity (PubMed:22511606). 4 Fe(2+) + 4 H(+) + O2 = 4 Fe(3+) + 2 H2O Monomer. Oligomer (By similarity). Interacts with NIFS1 (PubMed:22511606). Belongs to the frataxin family.