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Adenosine triphosphate phosphoydrolase activity associated with purified parainfluenza type 3 virions
Abstract:
An adenosine triphosphate phosphohydrolase associated with purified parainfluenza type 3 virions has been characterized. It hydrolyzed ATP to ADP and AMP when activated with Mg-2+ ions. Using Ca-2+ the production of ADP was inhibited but not that of AMP. Neither K+ NOR Na+ ions were required for the expression of maximal activity. Ouabain had no inhibitory effect on enzyme activity even at 10-3M. After exposure of virus preparations to Tween 20, enzyme activity was not affected. A linear relationship between enzyme activity and concentration of virus was observed.
Insights
This study characterizes the adenosine triphosphate phosphohydrolase enzyme in parainfluenza type 3 virions, detailing its activity with various ions and treatments for potential antiviral development.
Area of Science:
- Virology
- Enzymology
- Biochemistry
Background:
- Parainfluenza virus type 3 (PIV3) is a significant respiratory pathogen.
- Understanding viral enzymes is crucial for developing antiviral therapies.
Purpose of the Study:
- To characterize the adenosine triphosphate phosphohydrolase (ATP phosphohydrolase) activity associated with purified PIV3 virions.
- To investigate the enzyme's substrate specificity and cofactor requirements.
Main Methods:
- Purification of PIV3 virions.
- Enzymatic assays to measure ATP hydrolysis.
- Testing the effects of various divalent cations (Mg2+, Ca2+), monovalent ions (K+, Na+), and inhibitors (ouabain, Tween 20) on enzyme activity.
Main Results:
- The PIV3-associated enzyme hydrolyzed ATP to ADP and AMP, with Mg2+ as an essential activator.
- Ca2+ inhibited ADP production but not AMP production.
- Neither K+ nor Na+ were required for maximal activity.
- The enzyme was insensitive to ouabain and Tween 20 treatment.
- A linear correlation was observed between enzyme activity and virus concentration.
Conclusions:
- The characterized enzyme is an ATP phosphohydrolase intrinsic to PIV3 virions.
- Its specific ion dependencies and stability suggest potential as a target for antiviral interventions.