Substrate specificity of avian influenza H5N1 neuraminidase

Figure 2 The N1 activity on substrate specificity by Amplex Red^® assay. Substrate-specific neuraminidase activity of H5N1 avian influenza viruses isolated from animal (white bars) and human (black bars) was measured by a modified Amplex Red^® assay. The α2,3-linked sialoside specific activity was measured using Neu5Acα2,3LacNAcb-pAP as substrate (A), whereas the α2,6-linked sialoside specific activity was measured using Neu5Acα2,6LacNAcb-pAP (B). The fluorescence related to neuraminidase activity from triplicate experiments had been shown as mean ± SEM. In order to show substrate preference, ratios between the α2,3- and α2,6-specific activity are shown (C).