Some properties of mumps virus neuraminidase.

Mumps virus strains were characterized by the neuraminidase activity of infected allantoic and amniotic fluids of chick embryos. Ovomucoid was used as substrate for determination of neuraminidase activity. Storage of virus samples at 4 degrees C led to great losses of enzyme activity. Alkali chlorides, divalent cations, EDTA and N-ethylmaleimide exerted a low to medium inhibitory activity. Surfactants, depending on their type, caused inhibition, activation or no effect on the enzyme--substrate reactions. The pH optimum was 5.6 and 5.3 with mumps virus strains Enders and Jeryl Lynn, respectively. The Michaelis constants of 9.43 X 10(-3) and 7.57 X 10(-3) mol/1 allowed a differentiation of the two mumps virus strains based on their neuraminidase.