DYKDDDDK is used as an epitope tag. Epitope tags provide a method to localize gene products in a variety of cell types. DYKDDDDK tag, also known as Flag tag, can be introduced in N-term, C-term and internal position in recombinant proteins. The small size of the epitope tag and its high hydrophilicity does not alter protein e, Xenopus/Amphibian,pression,Porcineroteolytic maturation, antigenicity and function of the fusion protein. An enterokinase cleavage site allows for complete removal of the tag from the fusion protein. Flag is a registered trademark of Sigma-Aldrich.