Mechanism of Action of Staphylococcal Alpha-hemolysin. I. Some Factors Influencing the Measurement of Alpha-hemolysin.

Marucci, Americo A. (Upstate Medical Center, Syracuse, N.Y.). Mechanism of action of staphylococcal alpha-hemolysin. I. Some factors influencing the measurement of alpha-hemolysin. J. Bacteriol. 86:1182-1188. 1963.-A kinetic method for the accurate and reproducible measurement of the action of staphylococcal alpha-hemolysin on rabbit erythrocytes is described. The activity of the alpha-hemolysin depends upon the temperature used for measurement. At 37 C the hemolysin lyses cells faster, but it in turn is rather quickly inactivated. At 0 C there is no inactivation, but the rate of lysis is greatly decreased. There is no change in the activity with change in total reaction volume, providing that the concentrations of cells and hemolysin are kept constant. The fraction of rabbit red cells lysed by a given amount of hemolysin in a given time is constant and independent of the total number of cells in the reaction mixture.