Identification of Penicillin‐Stimulated Staphylococcal Haemolysin as Alpha‐Lysin

Cultivation of S. aureus in the presence of 0.03 IU benzyl-penicillin stimulated the formation of a haemolysin which was suggested to be alpha-lysin. Its molecular weight was estimated to be 30000 by molecular sieve chromatography. It was mainly active on rabbit erythrocytes and was neutralized by alphalysin antibody. Furthermore it gave a reaction of identity in comparative immunoelectrophoresis with an are which was shown to represent alpha-lysin.