Phosphoenolpyruvate-dependent hydrolysis of ONPG in toluene-treated cellsof Staphylococcus aureus.

Abstract

Intact cells of Staphylococcus aureus, strain AF 121,which had been grown in galactosecontaining broth, hydrolyzed o-nitrophenyl-β-D-galactoside (ONPG), a lactose analog, and released o-nitrophenol (ONP) into the medium. The activity was totally lost by treating the cells with toluene, but it was restored when phosphoenolpyruvate (PEP) was supplemented to the medium. Therefore, this method can be conveniently used for demonstrating the requirement of PEP for the ONPG-hydrolysis reaction in this organism. The activities obtained varied with conditions of the treatment. The highest activity was observed when the cells were treated with 6μl of toluene per ml for 30 min at 37℃.