HOW DOES THE FERRITIN CORE FROM

Ferritin stores iron as ferrihydrite inside a shell composed of H and L protein chains. H chains contain ferroxidase centres catalysing Fe2 oxidation, while L chains lack these centres but seem to promote ferr ihydrite nucleation. Mossbauer spectroscopic studies of recombinant H- chain ferritins show the following: (1) fast Fe2+ oxidation is associa ted with the formation of Fe3+ dimers at the ferroxidase centre; (2) w ithin 30 min, a portion of the dimers have split to Fe3+ monomers and some monomers have moved to the threefold channels; (3) over longer ti mes, a trend dimer --> monomer --> core is established. Core formation is accelerated if L chains are present.