Fig. (1) C-His₆ inhibition curve of complement mediated erythrocyte lysis. Antibody sensitized sheep erythrocytes were suspended in 1:20 human serum/gelatin veronal buffer (GVB) and treated with serial dilutions of C-His₆. The 100% lysis value was obtained by suspending cells in water and the minimal value was obtained by suspending cells in GVB only. The normalized data gave an EC₅₀ value of 9.37nM indicating that the peptide remained bioactive after incorporating the His₆-tag.