• Nature
  • Source
  • Conjugation

Associated products


Our Abpromise guarantee covers the use of ab7403 in the following tested applications.

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

  • Applications

    Dot blot


    Immunohistochemistry (Formalin/PFA-fixed paraffin-embedded sections)

    Immunohistochemistry (Frozen sections)



    Western blot

  • Form
  • Additional notes

    Horseradish peroxidase is conjugated to the streptavidin tetramer at ~1:1 molar ratio.

    ab7403 is stable for several weeks at 4°C as an undiluted liquid. Dilute only prior to immediate use.

    This product has been assayed against 1.0 µg of Biotinylated IgG in a standard capture ELISA using a peroxidase substrate as ABTS ab142041 as a substrate for 30 minutes at room temperature. A working dilution of 1:15,000 to 1:60,000 of the reconstitution concentration is suggested for this product. Optimal titers for other applications should be determined by the researcher.


  • Concentration information loading...

Preparation and Storage

  • Stability and Storage

    Shipped at 4°C. Upon delivery aliquot. Store at -20°C long term. Avoid freeze / thaw cycle.

    pH: 7.20
    Constituents: 0.424% Potassium phosphate, 0.87% Sodium chloride

General Info

  • Alternative names
    • SA V1
    • SA V2
    • strepavidin
    • Streptavidin V1
    • Streptavidin V2
    see all
  • Relevance
    Streptavidin is a tetrameric protein purified from Streptomyces sp. that binds very tightly to the vitamin biotin with a Kd of ~ 10-14 mol/l. The high affinity recognition of biotin and biotinylated molecules has made streptavidin one of the most important components in diagnostics and laboratory kits.
  • Cellular localization


  • IHC image of Histone H1 staining in a section of formalin-fixed paraffin-embedded [human normal colon]*. The section was pre-treated using pressure cooker heat mediated antigen retrieval with sodium citrate buffer (pH6) for 30mins. The section was then incubated with ab11080, 1/1000 dilution, for 15 mins at room temperature. A goat anti-mouse biotinylated secondary antibody (ab6788, 1/1000 dilution), was used to detect the primary, and visualized using an HRP conjugated ABC system. Streptavidin HRP was used, ab7403 at a 1/10000 dilution. DAB was used as the chromogen (ab103723), diluted 1/100 and incubated for 10min at room temperature. The section was then counterstained with haematoxylin and mounted with DPX. The inset negative control image is taken from an identical assay without primary antibody.

    For other IHC staining systems (automated and non-automated) customers should optimize variable parameters such as antigen retrieval conditions, primary antibody concentration and antibody incubation times.

    *Tissue obtained from the Human Research Tissue Bank, supported by the NIHR Cambridge Biomedical Research Centre

  • The wells were coated with ab200699 at 1µg/ml at 50µl/well overnight at 4°C, followed by a 5% BSA blocking step for 2h RT. Human IgG3 (ab138703) was then added starting at 20 µg/ml and plasma/serum at 1:500 and gradually diluted 1:4, 50µl/well for 2h. Ab201248 was then added at 1:10,000 dilution, 50µl/well for 2h. A HRP-streptavidin (ab7403) was used at 1:10,000 dilution for 1h.


This product has been referenced in:
  • Natoli ME  et al. Paper-based detection of HIV-1 drug resistance using isothermal amplification and an oligonucleotide ligation assay. Anal Biochem 544:64-71 (2018). Read more (PubMed: 29229373) »
  • Liang W  et al. Core Fucosylation of the T Cell Receptor Is Required for T Cell Activation. Front Immunol 9:78 (2018). Read more (PubMed: 29434598) »

See all 20 Publications for this product

Customer reviews and Q&As

Western blot
We performed modified biotin switch assay where the biotinylated sulfhydrated proteins were incubated with ab7403 - Streptavidin (HRP) for 1h at room temperature (1:100) and then immunoblotted for detection of sulfhydrated protein status.

Abcam user community

Verified customer

Submitted May 14 2018

I am sorry, but the components found in ab177848 are not separately available.
However, we have a very similar reagent sold as a standalone product, Streptavidin HRP (ab7403) https://www.abcam.com/streptavidin-hrp-ab7403.html.
It may take a bit...

Read More
A standard sandwich ELISA experiment worked very well by use of ab7403 with 1/30,000 dilution.

Detailed protocol was described below.

*5 uL of human serum was separated with size exclusion chromatography into 10 fractions.
*1st antibody : anti-CD9 (Ancell Corporation)
*Blocking : 5% BSA in PBS
*2nd antibody : Biotinylated anti-CD9 (Ancell Corporation)

*HRP label : ab7403 - Streptavidin HRP, 1/30,000 dilution in 1% BSA/PBS, 30 min, RT

*1-Step Ultra TMB-ELISA Substrate Solution - Pierce
*Measure OD 450 nm

Abcam user community

Verified customer

Submitted Aug 20 2014

Please thaw the content in tube and store it at 4C, it will be ok for several months (10-12 months). However if you want to store it for years then please aliquot it into smaller volume and then store it at -20C.

I have confirmed that we do do not have an antibody pair tested for ELISPOT but we do have a pair, ab109788 and ab83413, that have been tested together in sandwich ELISA. Both are rabbit polyclonal antibodies raised against full-length recombinant huma...

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Thank you for these details.

I have looked into your case, and as mentioned before, since we recommend storing this product at -20ºC and that it was stored at 4ºC for more than 2 months, we cannot guarantee this product. In addition...

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Thank you for contacting us.

It is normal that the colour that gives the HRP-TMB reaction fades when kept in the diluted form at 4ºC after it has previously been frozen.

This is because HRP is an enzyme and if it is frozen in ...

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Thank you for contacting us.

I am sorry to hear you are experiencing difficulties with one of our products. We take product complaints very seriously, and investigate every product that we feel may not be performing correctly.


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Vielen Dank für Ihre Anfrage.
Leider kann ich Ihnen nicht garantieren, dass diese Produkte für immer in unserem Katalog bleiben. Diese Entscheidung hängt von vielen Faktoren ab und wird von verschiedenen Abteilungen wie Marketing, Produktion etc. ...

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Thank you for contacting us.

We have not determined the molarity of this product. However, 94 kD (94,000 g/mole) would probably be an average MW for the product and the product has a concentration of 1 mg/ml. Therefore an approximate estimat...

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