Concentration-dependent block of hKv1.3 by recombinant Vm24, AnTx, and Ts6. A Hill equation (see Materials and Methods for details) was fitted to the averaged remaining current fraction (RCF) values calculated at different toxin concentrations as indicated. The best fit resulted in the Kd values shown at the top of each graph. Hill coefficients were H = 0.92 for Tag-Vm24 (panel (a)), H = 0.91 for Tag-AnTx, H = 0.95 for Untag-AnTx (panel (b)), H = 1.06 for Tag-Ts6, and H = 1.03 for Untag-Ts6 (panel (c)). Solid lines represent tagged peptide, dashed lines represent untagged peptides. Error bar represents SEM and n = 3–5.