CHEMICAL AND BIOLOGICAL PROPERTIES OF REDUCED AND ALKYLATED STAPHYLOCOCCAL ENTEROTOXIN B

The single disulfide bridge in staphylococcal enterotoxin B has been found to be nonessential for the biological activity and conformation of the protein. Reduction of the disulfide bridge and alkylation of the resulting -SH groups with both iodoacetamide and iodoacetate produced derivatives that had the same emetic activity and immunological properties as the native enterotoxin. Reduction and reoxidation of the disulfide bridge again did not produce any immunological or emetic changes. The physical properties of the alkylated enterotoxins and the reduced and oxidized enterotoxin, as measured by viscosity and sedimentation, remained essentially the same as that of the native enterotoxin. Unfolding in 6 M guanidine gave equivalent viscosities for the native and reduced carboxamidomethylated enterotoxins, and the derivative, after removal of the guanidine, regained full biological activity. (Author)