Biomineralization of iron: Isolation of ferritin from the hemolymph of the limpet Patella vulgata

Ferritin has been isolated from the hemolymph of the limpet Patella vulgata. The protein was homogeneous by electrophoretic criteria and appeared under the electron microscope as a central electron dense core surrounded by a polypeptide shell. The iron content of the protein was 22.5%, present in the central core which had a median diameter of 70–75 Å and was poorly crystalline. The polypeptide shell consisted of a single subunit of apparent Mr 25 000