Ni-NTA Agarose (25 ml)

QIAGEN offers an affinity chromatography matrix for purifying recombinant proteins carrying a 6xHis tag by gravity-flow chromatography. The matrix pairs Ni-NTA with a Sepharose CL-6B support and uses beads sized 45–165 µm, with a binding capacity of up to 50 mg/ml and a yield range of 100 µg – 100 mg. It is intended for large-scale manual batch and column purification starting from cell lysates.

The interaction between the histidine residues of the 6xHis tag and the immobilized nickel ions is conformation-independent, enabling one-step purification under native or denaturing conditions. NTA provides four chelation sites for nickel ions, which prevents nickel-ion leaching and delivers higher binding capacity and purity than three-site metal-chelating systems. The matrix is compatible with reagents including up to 6 M Gu·HCl, up to 8 M urea, up to 2% Triton X-100 or Tween 20, up to 20 mM β-mercaptoethanol, up to 50% glycerol, and up to 2 M NaCl. Imidazole can be used at 20 mM to suppress non-specific binding or at >100 mM to elute the 6xHis-tagged protein; alternatively, bound proteins are released under mild conditions with 100–250 mM imidazole or by lowering the pH.

Suitable for proteomics applications, the matrix can be used to purify His-tagged proteins from any expression system, including baculovirus, mammalian cells, yeast, and bacteria, and is also offered as a component of QIAGEN's QIAexpress Kits.