Stability and Resistance to Proteolysis of Enterotoxins SEC and SEL Produced by Staphylococcus epidermidis and Staphylococcus aureus .

The only staphylococcal enterotoxins produced by include SEC and SEL, whereas produces orthologous SECs and SEL having different sequences. We compared and SECs and SELs in terms of resistance to proteolysis and both, thermal and chemical stability. We show that SEC and SEL produced by have similar resistance to proteolysis if compared with their respective orthologues produced by . Studied and SEC variants incubated with pepsin at pH 2.0 were found to be more resistant to proteolysis than SELs. SELs turned out to be more resistant than SECs to proteolysis with trypsin at pH 8.0. SEC was found to be more resistant to thermal denaturation if compared with its orthologues. The and SEC variants were found to have higher thermal stability than SELs. Our data indicate that, due to their high stability, the enterotoxins SEC and SEL produced in food by may pose a food safety risk comparable with that posed by enterotoxins.