Bacterial hemolysins are exotoxins that attack blood cell membranes and cause cell rupture. Beta-hemolysin is a phospholipase C with specific activity toward sphingomyelins. Has a high specificity for sphingomyelin, hydrolyzes lysophosphatidylcholine at a much lower rate, but has no activity towards phosphatidylcholine, phosphatidylethanolamine, or phosphatidylserine. a 1,2-diacyl-sn-glycero-3-phosphocholine + H2O = a 1,2-diacyl-sn-glycerol + H(+) + phosphocholine Optimum pH is 6.5-7.5. Monomer. Less protein is secreted in a secG or double secG/secY2 mutant (at protein level). Belongs to the neutral sphingomyelinase family. Integration of phage DNA that disrupted the sequence. Integration of phage DNA that disrupted the sequence.