Abstract
The proteolytic enzymes produced by 11 Salmonella species of the Sub-genera I, II and IV, have been compared by a so-called enzymo-serological procedure. In sub-genus I, the enzymes of S. schleissheim and S. abortus-bovis showed an identical, or closely related, serological picture, whereas S. texas was serologically distinct. All the 7 examined strains of sub-genus II produced proteolytic enzymes which were serologically very similar, or identical. No enzymo-serological cross-reactions were observed between these organisms and the members of sub-genus I. The only examined species of sub-genus IV, S. argentina, was enzymo-serologically distinct from all other species. Intergeneric cross-reactions occurred between the enzymes from Salmonella species, Enterobacter (Aerobacter) cloacae and Serratia marcescens. The significance of these cross-reactions is discussed.