The present invention generally relates to polypeptide tags and the purification of polypeptides, proteins, and protein fragments displaying such tags. More particularly, the invention is directed to novel polypeptides, nucleic acid sequences and vectors encoding novel polypeptides containing antigenic determinants. Also provided are methods and kits for using such polypeptides for the purification of target peptides, as well as methods of constructing vectors encoding the novel polypeptides and the novel polypeptides linked to a target peptide.