Inhibition of hemolysis by zinc and its reversal by L-histidine.

Hemolysis induced by staphylococcal alpha-toxin, staphylococcal beta-toxin, streptolysin O, and streptolysin S was inhibited by zinc ions by virtue of inhibition of an early step in the events leading to lysis, presumably by preventing the lysins from attaching to the plasma membrane. In contrast, in hemolysis induced by Clostridium perfringens alpha-toxin and by perfringolysin O, a later step was inhibited by zinc. In hemolysis caused by saponin, lysolecithin, and Triton X-100, hemoglobin was precipitated by zinc ions as it was released from the erythrocyte. Inhibition by zinc was abolished by several amino acids of which L-histidine was the most effective.