Metal-chelating Sepharose consists of iminodiacetic acid groups coupled to Sepharose. It is supplied free of metal ions and has to be charged with a suitable metal ion before use. It is not always possible to predict which metal ion is most appropriate. The metal ions most frequently used are Ni2+, Cu2+, Zn2+. A single exposed histidine residue may result in adsorption of the protein on Cu2+ while two vicinal histidine residues are needed for adsorption on Zn2+, Ni2+ ions are often used for the purification of polyhistidine-tagged fusion protein. In some cases Cu2+, Co2+, and Ca2+ have been used with success.
Storage and Stability:May be stored at 4°C. For long-term storage, aliquot and store at 4°C. Do not freeze. Aliquots are stable for at least 12 months. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer
Note: We do not recommended adding glycerol as a cryopreservative.
