Some properties of mumps virus neuraminidase

Area of Science:

• Virology
• Enzymology
• Biochemistry

Background:

• Mumps virus is a significant human pathogen.
• Neuraminidase is a key enzyme in the viral replication cycle.
• Characterizing viral enzymes aids in understanding pathogenesis and developing antivirals.

Purpose of the Study:

• To characterize the neuraminidase activity of mumps virus strains.
• To investigate factors affecting neuraminidase activity, including storage, inhibitors, and pH.
• To explore the potential of neuraminidase kinetics for differentiating mumps virus strains.

Main Methods:

• Mumps virus strains (Enders and Jeryl Lynn) were propagated in chick embryos.
• Neuraminidase activity was determined using ovomucoid as a substrate in allantoic and amniotic fluids.
• Enzyme activity was assessed under various conditions: storage at 4°C, presence of alkali chlorides, divalent cations, EDTA, N-ethylmaleimide, surfactants, and different pH levels.
• Michaelis constants were calculated for kinetic analysis.

Main Results:

• Neuraminidase activity was significantly reduced upon storage of virus samples at 4°C.
• Alkali chlorides, divalent cations, EDTA, and N-ethylmaleimide showed low to medium inhibitory effects.
• Surfactants exhibited varied effects, including inhibition, activation, or no change in enzyme activity.
• The pH optima for neuraminidase activity were 5.6 for the Enders strain and 5.3 for the Jeryl Lynn strain.
• Distinct Michaelis constants (Km) were determined for each strain (9.43 x 10⁻³ mol/L for Enders, 7.57 x 10⁻³ mol/L for Jeryl Lynn).

Conclusions:

• Neuraminidase activity is sensitive to storage conditions and various chemical agents.
• The identified pH optima and Michaelis constants provide a basis for differentiating between mumps virus Enders and Jeryl Lynn strains.
• Characterization of viral neuraminidase offers insights into mumps virus biology and potential diagnostic markers.