Flag tag (DYKDDDDK) is a common, well-characterized hydrophilic tag. It is always used in conjunction with antibodies in protein pull-downs to study protein interactions. Flag tag can be incorporated on N-, C- or internal positions of the target protein.
HA tag (YPYDVPDYA) is derived from the human influenza hemagglutinin (HA) molecule corresponding to amino acids 98-106, and it is an ideal tag for co-IP and western blots, with small interference to the function of protein. HA tag has been extensively used as a general epitope tag in expression vectors.
His tag (HHHHHH) is the most common affinity tag used to purify proteins. His-Tag purification tag combined with metal chelate affinity chromatography provides a powerful tool for the separation and purification of recombinant proteins.
Myc tag (EQKLISEEDL) is a small, immunoreactive tag, and can be placed at the N- or C- terminus. Myc tag is a popular epitope tag for detecting the expression of recombinant proteins in yeast, bacteria, insect, and mammalian cell systems.