[Properties of Escherichia coli alpha-hemolysin].

SH-reagents (alpha-ethyl maleimide, n-chlor mercuribenzoate, dithioglycolic acid) and hydrogen peroxide induce insignificant changes in the activity of hemolysin. Reducing reagents (2-mercaptoethanol and ascorbate) inhibit hemolytic activity. Cholesterol at a concentration of 4.3 X 10(-5) M reduces this activity by 50%. Hemolysin has no phospholipase A activity. The energy necessary for activating the interaction of hemolysin with the membranes of erythrocytes (lag period) is 13800 cal/mol and for inducing the lysis of erythrocytes, 10 600 cal/mol. The above values are much less than those of O-labile hemolysins.