Ferritin

n. protein that stores iron for metabolism

Ferritin is a globular protein complex consisting of 24 protein subunits and is the main intracellular iron storage protein in both prokaryotes and eukaryotes, keeping it in a soluble and non-toxic form. Ferritin which is not combined with iron is called apoferritin.
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Ferritin /fer·ri·tin/ the iron-apoferritin complex, one of the chief forms in which iron is stored in the body. fer·ri·tin n. [more]Ferritin - Community and Resources

Noun
1. a protein containing 20% iron that is found in the intestines and liver and spleen; it is one of the chief forms in which iron is stored in the body
(hypernym) protein

n. ferritin, protein that stores iron for metabolism