Adenosine triphosphate phosphoydrolase activity associated with purified parainfluenza type 3 virions.

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.