The fluorometric neuraminidase assay method using 4-methylumbelliferyl-N-Ac-α-D-neuraminide as a substrate was investigated for the purpose of ascertaining its validity as a procedure for influenza viral neuraminidase antibody inhibition test.
The enzyme antibody inhibition titer obtained by the fluorometric assay system was far weaker than that obtained by the standard colorimetric neuraminidase assay method using fetuin as a substrate. Although solubilization of viral neuraminidase spikes with Triton X-100 increased the enzyme inhibition of antiserum to some extent, there is little possibility of using the fluorometric assay system for the purpose.