Ni Sepharose excel is an IMAC medium precharged with nickel ions very strongly bound to a chelating ligand

Ni Sepharose excel enables direct loading of samples without having to perform extensive and time-consuming pretreatment procedures. The flow properties of the medium make it excellent for purifications in a wide range of scales and allow loading of large sample volumes, enabling purification of low concentrations of target proteins at large volumes. Dynamic binding capacity was tested with 0.5 mg/ml (histidine)6-tagged pure protein (M_r 43 000) in EX-CELL™ 420 Insect serum-free medium (capacity at 10% breakthrough) or (histidine)6-tagged protein (M_r 28 000). Column volume was 1 ml and flow rate 1 ml/min. Binding capacity is sample-dependent.

Samples that usually cause stripping of metal ions can therefore be loaded to the medium. The nickel ions have been shown to remain bound to the chelating ligand even after incubation for 24 hours in 10 mM EDTA. Ni Sepharose excel is designed primarily for capture and purification of histidine-tagged proteins secreted into cell culture supernatants from eukaryotic cells such as insect cells or CHO cells.