Substrate specificity of the neuraminidase of different mumps virus strains.

The hydrolysis of neuraminlactose, fetuin, ovomucoid, kappa-caseinglycopeptide and mucine from the bovine submaxillary gland with the neuraminidase (NA) of mumps virus strains Jeryl Lynn, Enders and Berlin 9/76 was investigated to determine the pH-dependence of the reaction with the different substrates. The corresponding curves showed splitting into several peaks with reaction maxima ranging from pH 4.7 to pH 6.7. This occurred probably due to the heterogeneity of the virus samples. The NA of each virus strain had the best reaction affinity to neuraminlactose followed by decreasing affinities to ovomucoid, fetuin and kappa-caseinglycopeptide. The mucine from bovine submaxillary gland was not digested at all. The highest hydrolysis of each substrate was found with the Jeryl Lynn strain, which also possessed the lowest substrate specificity. It was followed by that of strain Enders and finally by isolate Berlin 9/76 which, in turn, had the highest substrate specificity. The lower substrate specificity of mumps virus NA seemed to correlate with a lower degree of its cytopathogenicity for hamster ependyma cells.