Molecular Weight of a Tobacco Seed Globulin

Abstract

In order to determine the structure of protein crystals from X-ray diffraction effects it is usually necessary to measure fairly large single crystals. An exception to this rule is the case of crystals belonging to the cubic system, for which powder photographs should provide sufficient data. A preparation of a cubic tobacco seed globulin isolated by H. S. Vickery of the Rockefeller Institute, New York, was given to us by Dr. D. M. Wrinch, and this we have examined by the X-ray method in the form of the dry powder.* The crystals were very small but well-formed isotropic octahedra.