A protein shell that stores iron in the body; it's ferritin without the iron atoms inside it.
From apo- (without) + ferritin, which comes from ferrum (iron in Latin) + -in (protein). Created in biochemistry to distinguish the empty storage protein from the iron-loaded version.
Your body makes apoferritin as a microscopic iron safe—when iron enters, it becomes ferritin; when your body needs iron again, apoferritin empties out and gets refilled, making it one of nature's most elegant storage-and-release systems.
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