POSITIVE STAINING OF PROTEIN MOLECULES FOR ELECTRON-MICROSCOPY - POLYIODINATION OF THE APOFERRITIN SHELL IN FERRITIN

Positive staining by attachment of multiple adventitious heavier atoms to protein molecules should be a useful preparative procedure for certain structural studies with electron microscopy. The present results demonstrates that positive staining by polyiodination permits the direct visualization of the protein shell (apoferritin) in ferritin molecules with conventional transmission electron microscopy.