NCCCC[[email protected]](NC(=O)[[email protected]](CC(O)=O)NC(=O)[[email protected]](CC(O)=O)NC(=O)[[email protected]](CC(O)=O)NC(=O)[[email protected]](CC(O)=O)NC(=O)[[email protected]](CCCCN)NC(=O)[[email protected]](Cc1ccc(O)cc1)NC(=O)[[email protected]@H](N)CC(O)=O)C(O)=O Description: DYKDDDDK, an eight-amino acid fusion tag with an enterokinase-cleavage site, was particularly developed for immunoaffinity chromatography. It provides for non-denaturing elution conditions. Various antibodies have been produced against this peptide. One antibody, indicated as M1, binds the peptide in the presence of bivalent metal cations, preferentially Ca2+. Chelating agents facilitate elution. Another approach is to use an excess of free DYKDDDDK peptide in competitive elution.