FIG 8.

Enzymatic activity of HN, WSN, and CA/09 NA proteins using monovalent and multivalent substrates. Specific activities of indicated N1 proteins determined by MUNANA assay (A) or by ELLA using fetuin (B) and transferrin (C) in combination with lectin ECA were graphed normalized to the activity of N1 HN. (D) Substrate specificities of the indicated N1 proteins were determined by ELLA using different glycoprotein-lectin combinations and graphed normalized to the specific activity determined with MUNANA. Means of 2 to 3 independent experiments performed in triplicate are shown for the MUNANA and ELLA assays. Standard deviations are indicated.