The glycolytic enzyme enolase of Staphylococcus aureus is a highly conserved enzyme which binds to human plasminogenthereby aiding the infection process. The cloning, overexpression and purification of S. aureus enolase as well as the effectof various metals upon the catalytic activity and structural stability of the enzyme have been reported. The recombinantenzyme (rSaeno) has been purified to homogeneity in abundant amounts (60 mg/L of culture) and the kinetic parameters(Km = 0.23 ± 0.013 9 10-3 M; Vmax = 90.98 ± 0.00052 U/mg) and the optimum pH were calculated. This communicationfurther reports that increasing concentrations of Na? ions inhibit the enzyme while increasing concentrations of K?ions were stimulatory. In case of divalent cations, it was found that Mg2? stimulates the activity of rSaeno while the rest ofthe divalent cations (Zn2+, Mn2+, Fe2+, Cu2+, Ni2+ and Ca2+) lead to a dose-dependent loss in the activity with a total lossof activity in the presence of Hg2+ and Cr2+. The circular dichroism data indicate that other than Hg2+, Ni2+ and to acertain extent Cu2+, none of the other ions destabilized rSaeno. The inhibitory roles of fluorides, as well as neurotoxiccompounds upon the catalytic activity of rSaeno, have also been studied. Conformational changes in rSaeno (induced byions) were studied using partial trypsin digestion.
Volume 46, 2020
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