Hemolytic and sphingomyelinase activities of Clostridium perfringens alpha-toxin are dependent on a domain homologous to that of an enzyme from the human arachidonic acid pathway.

The N-terminal domain of Clostridium perfringens alpha-toxin, homologous with the nontoxic phospholipase C of Bacillus cereus, was expressed in Escherichia coli and shown to retain all of the phosphatidylcholine hydrolyzing activity of the alpha-toxin, but not the sphingomyelinase, hemolytic, or lethal activities. The C-terminal domain of alpha-toxin showed sequence and predicted structural homologies with the N-terminal region of arachidonate 5-lipoxygenase, an enzyme from the human arachidonic acid pathway which plays a role in inflammatory and cardiovascular diseases in humans.