An anti-flag tag (FLAG fusion protein) is use to detect a FLAG-tag, or FLAG octapeptide, or FLAG epitope that is a polypeptide protein tag that can be added to a protein using recombinant DNA. This FLAG-tags have the sequence DYKDDDDK motiv. These tags are very useful to do protein purification by affinity chromatography. Also separation of recombinant, overexpressed proteins from cell lysates is done by FLAG go HIS tags. FLAGS are also used in the isolation of protein complexes with multiple subunits, because its mild purification procedure tends not to disrupt such complexes. It has been used to enrich proteins of height purity and quality to see the 3D crystal structure with x-ray. Suitable for in vivo use in cells. For electrophorese protein detection rabbit polyclonals anti Flag conjugation are the most suited antibodies.