Immunoprecipitation (IP) is a key technique in cellular and molecular biology, employed to isolate or purify specific antigens (proteins of interest) using solid phases like agarose or Sepharose™ resin, or magnetic particles. The IP method was initially performed on small aliquots of agarose resin and is used when scale-up is anticipated. Magnetic beads are versatile, enabling the targeting of single proteins or peptides (IP), studying protein interactions through protein complexes (Co-IP), identify regions of the genome with DNA-binding or RNA-binding proteins (ChIP or RIP), and exploring the functional dynamics of protein-nucleic acid interactions.

Advantages of magnetic beads for immunoprecipitation

Magnetic beads for IP have become more common, especially compared to the traditional method of using agarose slurries or resin for protein isolation. This is because magnetic immunoprecipitation beads provide several advantages over the traditional method, such as:

  • Low background—Little to no non-specific binding and no preclearing required for high-purity protein yields
  • Highly reproducible—Uniform composition of the magnetic beads helps ensure the most consistent results
  • Highly sensitiveMost-cited method for sensitive applications, such as ChIP and IP for low- abundance proteins
  • Fast and easy—<40 min protocol with no centrifugation or preclearing steps
  • Antibody savings—All binding occurs on the smooth outer surface of the beads, which conserves precious antibodies compared to porous agarose beads; using beads for IP is a cost-efficient solution per sample
  • Automation compatible—Immunoprecipitation beads protocol can be automated on the Thermo Fisher Scientific KingFisher platform

View common IP myths on agarose resins vs magnetic beads
Learn about co-immunoprecipitation


Immunoprecipitation beads selection guides

Antibody-binding magnetic beads for IP

 Protein A, G, A/GSecondary antibodies
(anti-mouse, anti-rabbit)
Recommended productsBeads only:Kits:Beads only:
Binding propertiesNon-covalent antibody binding
Antibody co-eluted off the beadsYes*
No (Pierce Crosslink Magnetic IP/Co-IP Kit)
Yes*
Type of ligandDifferent ligands bind different species and antibody subclasses with different specificity
  • Anti-mouse binds mouse IgG1, IgG2a, IgG2b
  • Anti-rabbit binds all rabbit IgGs
Non-specific bindingLow

* Crosslinking can be performed to avoid co-elution of the antibody, but this can decrease the yield of the target antigen.
† Learn which antibody-binding proteins are best for your IP antibody.

Learn more about how mass spectrometry and western workflows are enhanced by high-performance protein enrichment using Dynabeads and DynaGreen magnetic beads in our magnetic bead product brochure

Dynabeads magnetic beads compared to Sepharose- and agarose-based solutions

Figure 1. Shorter protocol time and better target protein yields with Dynabeads magnetic beads. Equal amounts of sample material with respect to Ab content and cell lysate volume were used for all IP protocols according to the manufacturer’s protocol. For the Dynabeads-based method, all the antibodies on the bead surface are accessible for optimal, highly reproducible antigen binding.

Dynabeads magnetic beads compared to competitor magnetic beads

Figure 2. Electron microscopy of Dynabeads magnetic beads compared to competitor magnetic beads. Dynabeads and DynaGreen magnetic beads have a defined surface to carry out the necessary binding, with no inner surface to trap any unwanted proteins. Dynabeads products (A) are the most uniform, monodisperse superparamagnetic beads, manufactured with highly controlled product qualities to help ensure the highest degree of purity and reproducibility, while the DynaGreen products (B) offer high purity and higher binding capacity vs. the Dynabeads products, but also offer a more sustainability-conscious version of Dynabeads products. Magnetic particles from alternative suppliers (C–E) have variable shapes and sizes that trap impurities, resulting in lower purity and reproducibility without proper functionalization and antibody coupling.


Dynabeads magnetic beads compared to competitor magnetic beads for IP

Figure 3. Dynabeads magnetic beads have exceptional immunoprecipitation performance with the combination of highest yield and lowest non-specific binding. (A) Silver staining of the protein membrane shows that Dynabeads magnetic beads have the most enriched binding at the antibody main band and very low non-specific binding with low signal/noise. (B) Western blot analysis of CD81 pulldown in Jurkat cells show that Dynabeads Protein G beads have the highest yield with a short ten-minute protein incubation.

Read tips on immunoprecipitation


Fusion tag-binding magnetic beads for IP

Tagc-MycFLAGHAHistidineGST
Description
  • Consists of a peptide (EQKLISEEDL) derived from the human c-myc oncogene (p62 c-myc)
  • Immobilized anti-c-Myc antibodies are used to immunoprecipitate c-Myc-tagged recombinant proteins
  • Consists of a peptide (DYKDDDDK) which is recognized by an immobilized high-affinity rat monoclonal antibody (clone L5)
  • Primarily used for the isolation of protein complexes with multiple subunits because the mild purification process tends not to disrupt these interactions
  • Consists of a peptide (YPYDVPDYA) derived from the human influenza hemagglutinin (HA) protein
  • Immobilized anti-HA antibodies are used to immunoprecipitate HA-tagged recombinant proteins
  • Consists of a string of six to nine histidine residues
  • Primarily used for purification via immobilized metal affinity chromatography (IMAC)
  • Consists of glutathione S-transferase (GST), a complete 211 amino acid protein (26 kDa)
  • Primarily used for purification via glutathione agarose resin

Recommended products

His and GST are not true epitope tags, because they are not usually purified or detected via specific antibodies. By contrast, HA and c-Myc tags are true epitope tags, because their only means of purification or detection is via specific antibodies. Epitope tags are seldom used for bulk purification but are most often used for IP or co-IP. Nevertheless, all four of these tag systems can be used for either purification or pull-down applications.

View fusion tag-binding bead options for IP


Biotin-binding magnetic beads for IP

If you have a biotinylated antibody (or ligand) that recognizes your protein, use of streptavidin beads is recommended

Main advantages of magnetic beads for biotin-binding:

 

  • If you have a sample rich in soluble IgGs
  • If you have a recombinant antibody lacking Fc regions
  • If you need a bead compatible with mass spectrometry
  •  

    Recommended productsDynabeads M-280 StreptavidinDynabeads MyOne Streptavidin T1*Pierce Streptavidin Magnetic Beads
    Description
    • Hydrophobic bead surface
    • Based on tosylactivated beads
    • Size distribution: CV <3%
    • BSA as blocking protein
    • Isoelectric point: pH 5.0
    • Low charge (–10 mV at pH 7)
    • Iron content (Ferrites): 12% (17%)
    • Hydrophobic bead surface
    • Based on tosylactivated beads
    • Size distribution: CV <3%
    • BSA as blocking protein
    • Isoelectric point: pH 5.0
    • Low charge (–10 mV at pH 7)
    • Iron content (Ferrites): 26% (37%)
    • Hydrophilic bead surface
    • Size distribution: 0.7–1.7 mm
    • Covalently pre-blocked (non-protein) to minimize nonspecific binding
    • pH range: 4–11
    • Iron content (Fe3O4): 60% (double layer of magnetite)
    • Particle density: ~2.0 g/cm3
    Capacity
    • Free biotin: 490–750 pmol/mg beads
    • Biotinylated Ig: 5–10 µg/mg beads
    • Free biotin: 950–1,500 pmol/mg beads
    • Biotinylated Ig: 20 µg/mg beads
    • Biotinylated fluorescein: 3500 pmol/mg
    • Biotinylated IgG: 55 mg/mg

    * Low sedimentation rate and improved reaction kinetics compared to M-280 beads.

    View streptavidin bead options for IP


    Surface-activated magnetic beads for IP

    If your target protein or ligand needs to be covalently coupled, use surface-activated beads

    Different ligands (antibodies, proteins, etc.) require different bead surface properties and immobilization chemistries. Choose surface-activated beads to control factors such as:

    • Hydrophobicity: choose hydrophilic of hydrophobic beads
    • Bead size: 1 µm, 2.8 µm, and 4.5 µm beads available
    • Surface chemistry: epoxy, amine, or tosylactivated

    View surface-activated bead options for IP

    Searching for high-performing, sustainable magnetic beads? Introducing DynaGreen Magnetic Beads.

    DynaGreen Magnetic Beads provide high-quality, reproducible results and are also environmentally friendly and microplastic-free. How do these beads contribute to a more sustainable science? All DynaGreen Magnetic Beads have the following features:

    • Non-microplastic bead core
    • Energy-efficient manufacturing
    • Reduced water consumption
    • Use of non-hazardous chemicals
    • Recyclable packaging
    • Paperless documents

    Learn more about DynaGreen Magnetic Beads

    Detect and analyze proteins in as little as 40 minutes

    With automation protocols available for KingFisher instruments, you can be ready to detect and analyze proteins in as little as 40 minutes with minimal hands-on time.

    Learn more about KingFisher automation


    What is immunoprecipitation?

    Immunoprecipitation (IP) is a cellular and molecular biology method used in laboratories to isolate or purify a specific antigen (or protein of interest) via a solid phase (agarose or Sepharose™ resin or magnetic particles). The IP method was first performed on small aliquots of agarose resin in microcentrifuge tubes. The IP method has evolved to use superparamagnetic particles to specifically target proteins of interest.

    View common IP myths and tips

    How does immunoprecipitation work?

    The Dynabeads magnetic beads IP procedure is simple, fast, requires no preclearing step, and results in high-target protein purity, yield, and consistent results. Both DynaGreen magnetic beads and Pierce magnetic beads can perform the same steps with slightly longer protocol times to complete. DynaGreen protocol finishes in <80 min. Pierce protocol finishes in <120 min.

    Step 1: Binding of the antibody to the beads

    Dynabeads, DynaGreen, and Pierce magnetic beads come pre-coated with protein A, protein G, anti-mouse IgG, or anti-rabbit IgG antibodies. Their rapid kinetics allow them to bind to the added antibody in about ten minutes (Figure 4). Biotinylated antibodies can also be used in combination with streptavidin-coupled Dynabeads and Pierce magnetic beads. After antibody incubation a wash step is performed to remove unbound antibodies.

    Step 2: Add sample to the beads

    The protein-containing sample is added to the beads-antibody mix and incubated for ten minutes to allow target protein binding. If the protein is of low abundance or low affinity, the incubation time can be increased to one hour or overnight. For most cases, a ten-minute incubation is sufficient.

    Step 3: Wash the protein-bound beads

    To help ensure high purity of the bound target protein, the beads should be washed 2 to 4 times with buffer on the magnet to remove all unbound proteins. This step in the isolation process helps ensure a high signal-to-noise ratio.

    Step 4: Elute the protein

    The protein can be eluted off the beads by using either a mild elution procedure or a denaturing elution procedure (Figure 5).

    Figure 4. Immunoprecipitation protocol with magnetic beads.

    Chart demonstrating denaturing elution is best used during SDS-PAGE; mild elution is best used for protein characterization, immunization, enzyme studies, amino acid sequence determination, and crystallization; and no elution is needed when performing protein-protein interactions studies, enzyme studies, bioassays, and immunoassays

    Figure 5. Types of elution buffers for immunoprecipitation with magnetic beads. Depending on your target protein and how they bind to the magnetic beads, there are three main types of elution buffers to unbind the target protein. Denaturing elution buffers are used for SDS-PAGE. Mild elution buffers are used for protein characterization, immunization, enzyme studies, amino acid sequence determination, and crystallization. Protein-protein interactions, enzyme studies, bioassays, and immunoassays may be performed without eluting your target protein from the magnetic beads.


    Videos on immunoprecipitation

    Covalent Coupling of Antibodies to Magnetic Beads - Fast and Efficient
    The benefits of the Dynabeads Antibody CoupliKit include: • Use any primary antibody • Get ultra-low non-specific binding • No need for cross-linking since Antibody is irreversibly bound to the beads and will not be eluted off with target protein
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      Immunoprecipitation with Dynabeads magnetic beads FAQs

      Here are some frequently asked questions regarding the use of Dynabeads magnetic beads for immunoprecipitation.

      A: Dynabeads Protein A and Dynabeads Protein G are 2.8-micron beads covalently coupled with Protein A and recombinant Protein G, respectively. Protein A and Protein G differ in their binding strength to immunoglobulins from different species and subclasses.

      View the Dynabeads product selection guide for detailed information on Ig species and subclass specificity to Dynabeads

      A: 1. Verify binding/specificity of your antibody to your antigen (e.g., by ELISA).

      2. Check the binding of your antibodies to the beads. If the antibodies are not captured and bound to the beads, the immunoprecipitation experiment will not work.

      3. If you have used the indirect method of immunoprecipitation, try the direct method. Conversely, if you have used the direct method, try the indirect method.

      4. Check the amount of beads and sample volume. With reference to the capacity of different beads proposed in the package inserts, increase the amount of beads or the concentration of your antibody during coupling.

      5. Increase the incubation time.

      6. Try another antibody.

      A: Yes, you can use the larger beads. Note: Smaller beads provide a larger surface area and therefore give higher yields of protein compared to the larger 4.5-micron beads.

      Immunoprecipitation publications using Dynabeads magnetic beads

      View publications on cell isolation using Dynabeads products
      View publications on Dynabeads Streptavidin magnetic beads

      Additional publications can be found in our Citations and References database. The database can be searched using a product catalog number or keyword. For example, searching with the term "10001D" will return a list of journal articles that cite the use of Dynabeads Protein A for Immunoprecipitation (Cat. No. 10001D) and searching with the term "dynabeads" will return a list of journal articles that cite the use of any Dynabeads product. Note that the Citations and References database on thermofisher.com contains only the small subset of scientific journal articles that cite the use of our products. Many more can be found via targeted searches of the PubMed™ database and similar databases.


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      Selection guide for Dynabeads products

      Dynabeads products are available for a multitude of molecular and cellular applications. Don’t know where to start? Use our easy selection guide that considers sample type, target molecule, and downstream application to provide tailored recommendations for Dynabeads products.

      Dynabeads product selection guide

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