Ferritin (apoferritin, iron-free form) (Apoferritin)

Apoferritin is the iron-free form of ferritin, a globular protein complex composed of 24 polypeptide subunits that self-assemble into a hollow, spherical shell. It serves as the precursor to ferritin, acquiring iron for storage and release as needed for cellular metabolism. Apoferritin itself has a molecular mass of approximately 450–480 kDa and forms a cage-like structure about 12 nm in diameter, with a 7–8 nm internal cavity where iron is stored once it is taken up. In mammals, the composition of the apoferritin shell may vary according to tissue due to a variable ratio of light (L) and heavy (H) chain subunits, which influences its properties. Its chief biological role is to act as a storage buffer for iron, protecting the cell from iron-mediated oxidative stress and helping maintain iron homeostasis. Unlike holoferritin (the iron-loaded form), apoferritin does not contain iron. Although it is not a classical therapeutic "target" like a receptor, enzyme, or transporter, it is of scientific interest in studies of protein aggregation and amyloid diseases, and as a nanomaterial scaffold. Apoferritin is not a therapeutic target in the conventional sense, nor is it typically the direct focus of drug development. However, ferritin (the iron-loaded form) plays key roles in iron metabolism disorders and is measured as a biomarker in blood, but this refers to ferritin overall, not specifically apoferritin. There is nothing wrong with the name "apoferritin," but it is more accurately a protein form rather than a conventional drug target. If structured, apoferritin should be mapped as an iron storage protein, not as the main active site of therapeutic agents.

Other names

Apoferritiniron-free ferritiniron-free ferritin protein