Relationships between Electrophoretic Patterns of Esterases from Salmonella

Abstract

Esterases of 85 strains of the 4 biochemically-defined subgenera of Salmonella, when analyzed by the acrylamide-agarose zymogram technique using several synthetic substrates, gave 4 principal bands (E1, E2, E3, E4) and 2 minor ones. The E1 esterase band hydrolyzed .alpha.-naphthyl acetate; the E2 band hydrolyzed .beta.-naphthyl acetate. These bands were resistant to di-isofluoropropyl phosphate (DFP) and their electrophoretic distribution among the strains occurred within a relatively small MF range, MF being the distance moved by the esterase band as a percentage of the distance moved by the dye front. The E3 band hydrolyzed .alpha.-naphthyl acetate and .alpha.-naphthyl butyrate and, to a lesser degree, .beta.-naphthyl esters; the E4 band hydrolyzed .alpha.-naphthyl acetate. These bands were sensitive to DFP and their electrophoretic distribution among the strains occurred in a wide MF range. All Salmonella strains were closely related in terms of their esterase profiles. The divergences in electrophoretic distribution of bands E3 and E4 were sufficient to recognize the subgenera of most of the Salmonella strains analyzed.