The FLAG™ peptide, a versatile fusion tag for the purification of recombinant proteins

Abstract

A fusion tag, called FLAG™ and consisting of eight amino acids (AspTyrLysAspAspAspAspLys) including an enterokinase-cleavage site, was specifically designed for immunoaffinity chromatography. It allows elution under non-denaturing conditions [Bio/Technology, 6 (1988) 1204]. Several antibodies against this peptide have been developed. One antibody, denoted as M1, binds the peptide in the presence of bivalent metal cations, preferably Ca+. Elution is effected by chelating agents. Another strategy is competitive elution with excess of free FLAG™ peptide. Antibodies M2 and M5 are applied in this procedure. Examples demonstrating the versatility, practicability and limitations of this technology are given. © 2001 Elsevier Science B.V. All rights reserved.