Characterization of the neuraminidase of the H1N1/09 pandemic influenza virus

► Sialidase activity of H1N1/09 and other human, swine and avian viruses was studied. ► 7:1 recombinant H1N1/09 viruses harboring different NAs were prepared and compared. ► H1N1/09 NA has distinctive substrate specificity. ► H1N1/09 NA and classical swine virus NA have similar functional characteristics.