Properties of ferritin from the earthworm Octolasium complanatum

Paolo Arosio, Sonia Levi, Elena Gabri, Simonetta Stefanini, Alessandro Finassi-Agro, Emilia Chiancone

Research output: Contribution to journalArticlepeer-review


The isolation and characterization of a protein with a high iron content from a common Italian earthworm (Octolasium complanatum) is described. This protein represents the first example of a purified ferritin from annelids. O. complanatum ferritin migrates on polyacrylamide gel electrophoresis with a mobility similar to that of horse spleen ferritin, and has hydrodynamic properties, i.e., elution volume and sedimentation velocity, which likewise correspond to those of horse ferritins. It can be resolved in a family of isoferritins with isoelectric points ranging from 6 to 7; accordingly, SDS gel electrophoresis reveals the presence of two subunit types of Mr 19700 and 20500, which are present in roughly equal amounts. O. complanatum ferritin crystallizes from poly(ethylene glycol) and is immunologically unreactive with antisera against human or horse ferritin. Apoferritin can be prepared by means of reducing agents, just like mammalian apoferritins. It catalyses iron oxidation and incorporation inside the protein shell under conditions that are known to lead to ferritin reconstitution. The spectroscopic properties of O. complanatum apoferritin indicate that the aromatic residues are immobilized in a hydrophobic environment, as in the case of mammalian apoferritins. Moreover, the presence of dichroic bands in the region 320-400 nm suggests that an extrinsic chromophore copurifies with earthworm ferritin.

Original languageEnglish
Pages (from-to)264-269
Number of pages6
JournalBiochimica et Biophysica Acta (BBA)/Protein Structure and Molecular
Issue number3
Publication statusPublished - Jun 28 1984


  • (Earthworm)
  • Ferritin
  • Iron storage

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology
  • Structural Biology


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