Epitope Tagging: From His to OLLAS

Epitope tagging is a procedure that inserts a short amino acid sequence into a protein within an expression vector via genetic engineering. Antibodies that recognize the tag can then be used to detect the protein when no antibody to the target protein exists or when the target protein shows low immunogenicity.  Such tags can be inserted at the C-terminus, N-terminus or even within the protein itself.  Terminal insertion is preferred as internal tags may alter protein function or become buried within the tertiary structure of the protein.