Ni-NTA Magnetic Agarose Beads

For high-throughput, micro-scale purification of His-tagged proteins and versatile magnetocapture assays using His tags

  • Directed presentation for enhanced signal-to-noise and reproducibility
  • Wide range of binding capacities by varying the number of beads
  • Effective screening procedures even with crude cell lysates
  • Ideal for study of biomolecular interactions
  • Options for full automation

Ni-NTA Magnetic Agarose Beads are magnetic particles coated with Ni-NTA Agarose affinity purification matrix. They are used for immobilizing and purifying recombinant proteins carrying a His tag. Histidine residues in the His tag bind to the vacant positions in the coordination sphere of the immobilized nickel ions with high specificity and affinity. Once proteins are bound, the beads can be precipitated using a magnet, washed, and proteins eluted in small volumes of buffer under native or denaturing conditions.

Product Cat. no. List price:
Ni-NTA Magnetic Agarose Beads (2 x 1 ml)
2 x 1 ml nickel-charged magnetic agarose beads (5% suspension). This product will be discontinued as of June 30, 2021 or until stocks last. We recommend Ni-NTA Magnetic Agarose Beads (6 x 1 ml).
Ni-NTA Magnetic Agarose Beads (6 x 1 ml)
6 x 1 ml nickel-charged magnetic agarose beads (5% suspension)
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Ni-NTA Magnetic Agarose Beads are intended for molecular biology applications. These products are not intended for the diagnosis, prevention, or treatment of a disease.
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Micro-scale protein purification.|Micrograph of Ni-NTA Magnetic Agarose Beads.|
|Magnetic particles are seen inside the beads.|

The QIAexpress Ni-NTA Protein Purification System, including the Ni-NTA Magnetic Agarose Beads (see figure Micrograph of Ni-NTA Magnetic Agarose Beads) is based on the remarkable selectivity of patented Ni-NTA (nickel-nitrilotriacetic acid) resin for proteins containing an affinity tag of six or more histidine residues — the His tag. This technology allows one-step purification of almost any His-tagged protein from any expression system under native or denaturing conditions (see figure Protein purification with the Ni-NTA protein purification system). NTA, which has four chelation sites for nickel ions, binds nickel more tightly than metal-chelating purification systems that only have three sites available for interaction with metal ions. The extra chelation site prevents nickel ion leaching and results in a greater binding capacity and protein preparations with higher purity than those obtained using other metal-chelating purification systems. The QIAexpress system can be used to purify His-tagged proteins from any expression system including baculovirus, mammalian cells, yeast, and bacteria.


The purification of His-tagged proteins consists of 4 stages: cell lysis, binding, washing, and elution (see figure Micro-scale protein purification). Purification of recombinant proteins using the QIAexpress system does not depend on the 3-dimensional structure of the protein or His tag. This allows one-step protein purification under either native or denaturing conditions, from dilute solutions and crude lysates. Strong denaturants and detergents can be used for efficient solubilization and purification of receptors, membrane proteins, and proteins that form inclusion bodies. Reagents that allow efficient removal of nonspecifically binding contaminants can be included in wash buffers (see table). Purified proteins are eluted under mild conditions by adding 100–250 mM imidazole as competitor or by a reduction in pH.


Reagents Compatible with the His/Ni-NTA Interaction
DenaturantsDetergentsReducing agents Others Salts For long-term storage
6 M Gu·HCl 2% Triton X-100 20 mM β-ME 50% glycerol 4 M MgCl2 Up to 30% ethanol
8 M urea 2% Tween 20 10 mM DTT 20% ethanol 5 mM CaCl2 or 100 mM NaOH
 1% CHAPS 20 mM TCEP20 mM imidazole 2 M NaCl  




The QIAexpress Ni-NTA Protein Purification System, including the Ni-NTA Magnetic Agarose Beads, provides reliable, one-step purification of proteins suitable for any application, including:

  • Structural and functional investigations
  • Crystallization for determination of three-dimensional structure
  • Assays involving protein–protein and protein–DNA interactions
  • Immunization to produce antibodies
Applications Proteomics
Bead size 20–70 µm
Binding capacity Up to 2 mg/ml suspension (5%)
Processing Automated/manual
Scale Micro scale
Special feature High throughput (96-well)
Start material Cell lysate
Support/matrix Magnetic agarose beads
Tag 6xHis tag
Yield <10 mg protein per column

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Kit Handbooks
For Manual and automated Assays using 6xHis-tagged proteins Purification of 6xHis-tagged proteins
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