In the present experiments we attemped to fractionate horse spleen ferritin and apoferritin on an electrofocusing column and obtained eight or nine heterogenous peaks in a pH range of 4.22 to 4.6, which were grouped into three main components. There was no significant difference between the fraction patterns of horse spleen ferritin, monomeric ferritin and apoferritin. The heterogeneity demonstrated in the present paper represents polymorphic forms of ferritin rather than polymeric forms as hitherto described. © 1971.
Urushizaki, I., Niitsu, Y., Ishitani, K., Matsuda, M., & Fukuda, M. (1971). Microheterogeneity of horse spleen ferritin and apoferritin. BBA - Protein Structure, 243(2), 187–192. https://doi.org/10.1016/0005-2795(71)90075-4