Membrane bound F1Fo ATP synthase was preincubated for 60 min at room temperature with varied concentrations of venom peptides, OH-CATH, (KF-34), cathelicidin (BF-30), lycotoxin I (IL-25), or lycotoxin II (KE-27). The Materials and Methods section contains the detailed procedure. Data points are the average of three to four experiments, using 2–3 independent membrane preparations. Results agreed within ± 5%.