Dissociation-association properties of apoferritin in the milligram and microgram range

Abstract

Concentration dependent association of the 17 S unit of horse spleen apoferritin leads to dimer formation at c ∼ 0.1 mg/ml; at c > 0.4 mg/ml trimers and higher aggregates are formed. Dissociation into subunits is not detectable at concentrations as low as 10 −2 or 10 −4 mg/ml using sedimentation velocity or gel chromatography, respectively. In accordance with iron incorporation into the preformed protein shell as the basic mechanism of ferritin formation, the results suggest the quaternary structure of apoferritin to be stable under quasi physiological conditions.