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Prometheus™ Co-IDA Agarose resin is an affinity chromatography resin for purification of histidine-tagged proteins by Immobilized Metal Affinity Chromatography (IMAC). It binds to six histidine residues (6x His), a common tag used in protein purification and consists of iminodiacetate (IDA - a tridentate chelating agent) coupled to 6% cross-linked agarose beads. The IDA binds divalent cobalt ion with a capacity of 20-40umoles Co2+/ml resin. The protein binding capacity is >50mg protein per ml resin, but we have demonstrated binding of >130mg of purified DHAK-6XHis tagged protein to a ml of resin.
Although His-tagged proteins bind to Co-IDA with a slightly lower efficiency compared to Ni-IDA Agarose, there is a significant reduction in non-specific binding. Cobalt resins offer higher selectivity for poly-His sequences, but they have a low loading capacity. Therefore Cobalt Chelating Resin should be used for valuable recombinant proteins in limited quantities. The purity and yield of the target protein varies and is dependent on many factors including working conditions, size, conformation, expression levels, solubility and sample impurities.