Abstract
The molecular weight of turnip yellow mosaic virus and its weight fraction of RNA were measured. The mass of the virus was found to be 5·5×10
6 for the necrotic Rademacher strain and 5·7×10
6 for the savoy strain. The weight fraction of RNA was 0·35. These values are consistent with the model of the virus having only two species of macromolecules: the viral RNA and 180 identical polypeptide chains.