Bacterial hemolysins are exotoxins that attack blood cell membranes and cause cell rupture by forming a pore. The Gly-rich region is probably involved in binding calcium, which is required for target cell-binding or cytolytic activity. The three transmembrane domains are involved in pore formation by the cytotoxin. Myristoylated by HlyC; the toxin only becomes active when modified (PubMed:7801126, PubMed:8808931, PubMed:10978310, PubMed:32461253). Mainly myristoylated, while a minor fraction is acylated with pentadecanoyl (C15:0; 26%) and heptadecanoyl (C17:0; 6%) fatty acyl groups (PubMed:10978310). Fatty acylation is involved in binding to host membranes and promotes the irreversible insertion of Hemolysin into the host cell membrane (PubMed:12598051). Can be activated by both myristoylation and palmitoylation, but HlyC catalyzes lysine myristoylation (PubMed:32461253). The hemolysin of E.coli is produced predominantly by strains causing extraintestinal infections, such as those of the urinary tract. Belongs to the RTX prokaryotic toxin (TC 1.C.11) family.