Sialidase activity of swine H1N1 and avian H5N1 rNAs.

(A) Kinetic analyses of rNAs. Triplicate data sets for each experiment were used to calculate the steady-state velocity at decreasing concentrations of MuNANA substrate for each enzyme, and were expressed as initial rates (μM/s) vs concentration of substrate. The reactions containing 0.2 nM of enzyme and 0.59–600 μM of MuNANA were performed at 37°C in 200 mM NaOAc, 20 mM CaCl₂, 0,01 mg/ml BSA, pH5.5. (B) Titration of rNAs activity by ELLA. Decreasing amount of rNAs were incubated with a fixed amount of fetuin overnight at 37°C and OD detected were graphed vs the protein concentration. Data represent mean±SD of 3 independent experiments performed in duplicate.