The V5 tag is a 14 amino acid peptide derived from a small epitope on the P and V proteins of simian virus 5 (SV5), a member of the paramyxovirus family. This peptide can be expressed and detected with the protein of interest as an amino-terminal or carboxy-terminal fusion. Because of its small size, V5 tag is unlikely to affect the tagged protein’s biochemical properties. V5 tag is useful for the labeling and detection of proteins using immunoblotting, immunoprecipitation, and immunostaining techniques.
VHH are single-domain antibodies derived from the variable regions of heavy chain of Camelidae immunoglobulin. The size of VHH is extremely small(<15KDa) compared to other forms of antibody fragment, which significantly increase the permeability of VHH. Thus VHH is considered of great value for research, diagnostics and therapeutics.