• Product name

    Anti-IgE Affibody® Molecule
  • Specificity

    This Anti-IgE Affibody® Molecule is modified with a unique C-terminal cysteine for directed single-point chemical modification, facilitating labelling with fluorescent dyes, biotin or coupling to matrices. However, tail-to-tail dimers are spontaneously generated via a disulphide bridge between the C-terminal cysteines. Prior to coupling via the C-terminal the Affibody® Molecule needs to be reduced to expose the reactive cysteine residue. Recommended reducing condition is 20mM DTT at a pH above 7.5 and incubation at room temperature for 2 hours. Remove excess DTT by passage through a desalting column, not by dialysis.
  • Tested applications

    Suitable for: ELISA, Dot blotmore details
  • Species reactivity

    Reacts with: Human
  • Immunogen

    Other Immunogen Type corresponding to Human IgE.

  • General notes

    ab31899 is a recombinant protein produced in E. coli.

    What are Affibody Molecules?
    Affibody® affinity ligands are unique research reagents, produced using innovative protein-engineering technologies. They are small, simple proteins composed of a three-helix bundle based on the scaffold of one of the IgG-binding domains of Protein A. Protein A is a surface protein from the bacterium Staphylococcus aureus. This scaffold has excellent features as an affinity ligand and can be designed to bind with high affinity to any given target protein. The domain consists of 58 amino acids, 13 of which are randomized to generate Affibody® libraries with a large number of ligand variants. Thus, the libraries consist of a multitude of protein ligands with an identical backbone and variable surface-binding properties. In function, Affibody® Molecules mimic monoclonal antibodies. Compared to antibodies, the most striking dissimilarity of Affibody® Molecules is the small size. Affibody® Molecules have a molecular weight of 6kDa, compared to the molecular weight of antibodies, which is 150kDa. In spite of its small size, the binding site of Affibody® Molecules is similar to that of an antibody. The advantages of Affibody® Molcules over antibodies are: -their small size -the simple structure of the molecules -its robust physical properties; able to withstand a broad range of analytical conditions, including extreme pH and elevated temperature -its ability to fold correctly intracellularly -the fast and cost effective production in bacteria -the potential to couple Affibody® Molecules in multimeric constructs Affibody® Molecules have highly competitive properties for applications within affinity purification, sample preparation, protein detection and in vitro diagnostics.


  • Form

  • Storage instructions

    Shipped at 4°C. Store at +4°C short term (1-2 weeks). Upon delivery aliquot. Store at -20°C long term.
  • Storage buffer

    pH: 7.4
    Constituents: 0.079% Ammonium bicarbonate, PBS
  • Concentration information loading...
  • Purification notes

    ab31899 is >98% pure, as determined by SDS-PAGE (Coomassie blue staining) and RP-HPLC analysis.
  • Research areas

  • Relevance

    IgE is the class of antibodies produced in the lungs, skin, and mucous membranes. It may protect against parasite invasion, but it is a major factor in allergic reactions. The antigen-specific IgE interacts with mast cells and eosinophils, triggers the release of histamine, leukotrienes and other substances that lead to the itching, sneezing and congestion of allergies - and the life threatening respiratory distress of asthma and anaphylactic shock.
  • Cellular localization

    Cell Membrane
  • Alternative names

    • Igh2
    • IGHE
    • IGHEP1
    • Immunoglobulin heavy constant epsilon
  • Database links


Our Abpromise guarantee covers the use of ab31899 in the following tested applications.

The application notes include recommended starting dilutions; optimal dilutions/concentrations should be determined by the end user.

Application Abreviews Notes
ELISA Use at an assay dependent dilution. This product is an ideal affinity ligand as a capture reagent in ELISA.
Dot blot Use at an assay dependent dilution. For use as a detection reagent.


  • Standard IgE was titrated on Anti-IgE Affibody® molecule coated plates with a sensitivity of 20 ng/ml.


    The Anti-IgE Affibody® molecule can be used as capture reagent in a sandwich ELISA in combination with a mouse anti-human IgE monoclonal antibody as the detection reagent. Titration of IgE gives a sigmoid curve with a sensitivity of 20 ng IgE/ml (defined as two times background value) and a measurement interval between 100 and 500 ng/ml.

  • The concentration of IgE was anlalyzed in 10% diluted, IgE spiked serum sample on Anti-IgE Affibody® molecule coated plates.


    It was investigated if serum proteins interferes with the capture capabilities of the Anti-IgE Affibody® molecule in a serum sample. Human serum was diluted ten times and IgE was added to a final concentration of 2 ug/ml. Standard IgE and serum spiked with IgE was titrated on Anti-IgE Affibody® coated ELISA plates in twofold dilution series. The ELISA was performed as described in the protocol. As shown in the figure, the standard curve (red line) and the result from the titration of serum IgE (blue line) are almost identical suggesting that serum proteins do not interfere with the IgE binding.


ab31899 has not yet been referenced specifically in any publications.

Customer reviews and Q&As

1-3 of 3 Q&A


Mw: 13.5 kDa Theoretical pI: 4.2 Concentration conversions: 1 Abs280 = 1.17 mg/ml 1 mg/ml = 0.85 Abs280 units Molar extinction coefficient: 11500 M-1 cm-1 I hope these figues are helpful. Please contact me again if you would like anything further.

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This Anti-IgE Affibody® molecule contains 10 Lysines, none of them placed in the binding region. Please see schematic amino acid sequence, where amino acids in part of the molecule have been replaced by "X". We have not tested amine labelling, but we think it might work. GSSLQVDNKFNKEXXXXXXXXXXLPNLNXXXXXXXXXXXXDDPSQSANLLAEAKKLNDAQAPKVDNKFNKEVLNAVAEITGLPNLNWAQQDAFIFSLLDDPSQSANLLAEAKKLNDAQAPKVDC I hope this is helpful. Please contact us again if you need any further information.

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Thank you for your enquiry. I apologize for the delay in getting back to you. The Anti-IgE Affibody(r) molecule has been tested to bind to CH4 of IgE. I hope this information helps, please do not hesitate to contact us if you need any more advice or information.

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