THE MOLECULAR STRUCTURE OF ISOLATED AND INTRACELLULAR FERRITIN

¹ Department of Anatomy, University of Edinburgh

The ferritin molecule consists of a central nucleus of high iron content, surrounded by a shell of protein approximately spherical in shape. This study with the electron microscope suggests that this iron is stored in six micelles arranged at the corners of a regular octahedron. This structure can be demonstrated in isolated crystallizable ferritin and it permits the identification of single molecules of ferritin in sections of tissues. The implications of an octahedral micellar form are discussed in relation to the shape of the protein coat and the crystal structure.

Note:

I am grateful to Dr. J. F. Wilkinson of the Department of Bacteriology, who isolated the ferritin from human and horse spleens, and to Professor G. J. Romanes and Dr. G. H. Haggis who made valuable suggestions during the preparation of this paper. The microscope, which is on permanent loan from the Wellcome Foundation, was maintained by Mr. G. Wilson. The photographs were prepared by Mr. H. Tully and part of the cost of their reproduction was borne by the Carnegie Trust.