Figure 5
From: Influenza A penetrates host mucus by cleaving sialic acids with neuraminidase
Sia cleavage preference and susceptibility to oseltamivir inhibition. (A) The cleaving preference of IAV NA was tested by incubation of IAV with the fluorescent reporter, 4-methyl-umbelliferyl (4MU), linked to Neu5Ac, Neu5Gc, or 2-keto-3-deoxynononic acid (Kdn) as substrate. All virus strains cleaved Neu5Ac and Neu5Gc but not Kdn. Background from spontaneous degradation of the 4MU-Sia compounds was subtracted from the results. (B) Virus susceptibility to oseltamivir inhibition was tested by incubation of IAV with 2.5 nmol 4MU-Neu5Ac in the presence of 0, 1 or 17.5 μM oseltamivir in triplicates. Certain strains were only partially inhibited by 1 μM oseltamivir, however, all of the strains were inhibited by 17.5 μM oseltamivir. Substrate cleavage was quantified by measuring fluorescence from the released 4MU reporter compound. *P<0.05, **P<0.01 (two-tailed T-Test, n=3).