REASSEMBLY OF APOFERRITIN MOLECULES FROM SUBUNITS

APOFERRITIN, the protein component of the iron-storage protein ferritin, consists of twenty polypeptide chains, each of molecular weight about 23,000, arranged symmetrically to form a hollow shell1. In the ultracentrifuge apoferritin molecules sediment with a coefficient S°20,w, equal to 17.6S (ref. 2). Negatively stained preparations of apoferritin show molecules with circular profiles about 105 in diameter, many molecules being penetrated by stain to give an annular appearance3. Ferritin consists of a mixture of molecules, some of which are empty shells, while the majority have shells which are filled, or partially filled, with a core of a hydrated ferric oxide-phosphate complex4. The experiments reported here were designed to investigate the possible dissociation and reassembly of apoferritin and ferritin. © 1968 Nature Publishing Group.