The anti-DYKDDDDK tag affinity gel is composed of the L5 antibody conjugated to an agarose resin, which can be used for purification of proteins expressing the octapeptide, DYKDDDDK. The DYKDDDDK tag, commonly referred to as Sigma(R)'s FLAG(R) Tag, is often used as a protein modification in order to simplify the labeling and detection of proteins. The binding capacity of the L5 agarose resin is greater than 0.8 mg/ml. The resin can be re-used at least five times (see technical bulletin for regeneration and storage). This affinity gel is also useful for immunoprecipitation of DYKDDDDK-tagged protein.