Ferritin-apoferritin system

In order to deal with a system whose structural characteristics were unaltered by the loading with Gd(III) chelates, we choose Apoferritin because it allows the Imaging Probes to be entrapped inside its inner cavity (60). The exterior of such Gd(III)-loaded Apoferritin is exactly the same as in the parent Ferritin and then, once administered intravenously, it is quickly cleared-up by the proper receptors on hepatocytes (172). The process of loading Apoferritin with [GdHPD03A(H20)] consists first of the dissociation of the protein into subunits at pH 2, followed by its reforming at pH 7, thereby trapping the solution components (e.g., [GdHPD03A(H20)])... 

A storage form of iron consisting of ferric hydroxide and ferric phosphate attached to the protein apoferritin. It is found in the reticulo-endothelial system, the liver and muscle. The ferritin in plasma is in equilibrium with the ferritin in iron stores. Thus low plasma levels may suggest iron deficiency while high plasma levels suggest iron overload. It can be measured by immuno-radiometric assay. 

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