The Nature of Staphylococcal Beta Hemolysin: I. Mode of Action

The mode of action of highly punned beta hemolysin derived from the R-1 strain of Staphylococcus aureus has been investigated. Sphingomyelin was absent from lipid extracts of sheep erythrocytes treated with beta hemolysin when compared to normal cells. A correlation was also established between the sphingomyelin content of other erythrocyte species and their sensitivity to beta hemolysin. Further investigations revealed that sphingomyelin is hydrolyzed to yield phosphorylcholine and N-acyl sphingosine. Thus, the mode of action of the beta hemolysin is like that of phospholipase C. Various phosphate compounds other than sphingomyelin, including RNA, glycerophosphate, phenyl-phosphate, phosphatidylethanolamine, and phosphatidylcholine were tested as substrates, but virtually no hydrolysis was observed. In contrast with the results of other workers, R-1 beta hemolysin did not release detectable amounts of carbohydrate from staphylococcal cell walls.