A cholesterol-dependent toxin that causes cytolysis by forming pores in cholesterol-containing host membranes. After binding to target membranes, the protein assembles into a pre-pore complex. A major conformational change leads to insertion in the host membrane and formation of an oligomeric pore complex. Cholesterol is required for binding to host cell membranes, membrane insertion and pore formation; cholesterol binding is mediated by a Thr-Leu pair in the C-terminus. Can be reversibly inactivated by oxidation.

> 90% as determined by SDS-PAGE.