Sedimentation and diffusion constants were determined for electrophoretically purified Vi antigen before and after mild alkaline hydrolysis. The molecular weight of the intact antigen was found to be 1.7 X 106. Mild alkaline hydrolysis completely removed 0-acetyl, reduced the molecular weight to 1.0 x 105, and lowered the intrinsic viscosity from 8.0 deciliters/g to approximately 0.5 deciliter/g. Infrared spectra of the two antigen preparations were also compared.

Several investigators have attempted to purify the Vi antigen and have described their products in terms of chemical and biological properties

No abstract