Sensorgrams of the melittin–POPC interaction using single-cycle kinetics for the mid-range concentrations. Following immobilization of POPC liposomes (1 mM lipid) to a binding response of ~4500 RU, increasing concentrations of melittin (0.3, 0.6, 0.9, 1.2 and 1.5 µM) were serially injected in a single-cycle at a flow rate of 30 µL/min for 80 s with a single regeneration step with 10 mM glycine–HCl (pH 2.5) at the end, i.e., after all five concentrations of melittin. Binding kinetic analysis of the sensorgrams with a Langmuir 1:1 model (A) and a two-state reaction model (B) were conducted using BIAevaluation® software. The estimated rate constants and affinity values, based on both these models, are listed in Table 1 and Table 2.