STAPHYLOCOCCAL TOXINS: IV. FACTORS AFFECTING HEMOLYSIS BY β-LYSIN

Abstract

The effects of a number of factors upon hemolysis by staphylococcal β-lysin have been examined. It has been found that crude β-lysin loses much of its hemolytic activity upon dialysis, but activity is restored by addition of magnesium or manganese ions. At optimum levels (0.01–0.015 M) of magnesium, hemolytic activity may be 35 times as great as that of dialyzed lysin. Lytic activity is maximal at neutral reactions but decreases sharply below pH 6.8. Addition of gelatin or albumin to the system causes β-lysin to exhibit increased hemolytic activity. This increase is not due, however, to protection of the lysin against spontaneous loss of activity in dilute solution. A typical time-hemolysis curve is sigmoid and a family of similar curves distributed along the time axis may be obtained with a series of different lysin concentrations. Relative β-lysin concentrations may be determined under defined conditions of erythrocyte, buffer, gelatin, and magnesium ion concentrations and at pH 7.0 employing concentrations of lysin which cause not less than 10, and not more than 75–80% hemolysis.