Enzymatic Properties of the Neuraminidase of Recombinant H5N1 Influenza Viruses.

aNA inhibition assay was performed with viruses standardized to equivalent NA activity and incubated with NA inhibitors (0.00005–100 µM) and MUNANA substrate. IC50 was determined by plotting the dose-response curve of inhibition of NA activity as a function of the compound concentration. Values represent 3 independent determinations.
bKm represents a half-maximal catalytic rate. The enzyme kinetic data were fit to the Michaelis-Menten equation using GraphPad Prism 4. Values are the mean ± SD from one representative experiment done in triplicate.
cRatio of the respective viruses’ NA Vmax to the Vmax of WT recombinant A/Turkey/15/06 virus NA. Vmax was calculated using a nonlinear regression of the curve according to the Michaelis-Menten equation.
dDetermined by enzymatic kinetic analysis and calculated using nonlinear regression of the plot of initial velocity as a function of inhibitor concentration.
*P<0.01 compared to WT virus (one-way ANOVA).