• 产品名称

  • 生物活性

    Binds to Biotin. Dissociation constant has not been measured.

  • 表达系统

  • Accession

  • 蛋白长度

    Full length protein
  • 无动物成分

  • 性质

    • 种属

      Streptomyces avidinii
  • 偶联物

  • 描述

    Native Streptavidin蛋白(HRP)



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.

  • 应用

    Dot blot


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

    Immunohistochemistry (Frozen sections)



    Western blot

  • 形式

  • 补充说明

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

    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...


  • 稳定性和存储

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

    pH: 7.20
    Preservative: 0.01% Gentamicin sulphate
    Constituents: 0.424% Potassium phosphate, 0.87% Sodium chloride, BSA

    This product is an active protein and may elicit a biological response in vivo, handle with caution.


  • 别名

    • SA V1
    • SA V2
    • strepavidin
    • Streptavidin V1
    • Streptavidin V2
    see all
  • 相关性

    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.
  • 细胞定位



  • 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:

  • Guo J  et al. Detection and identification of O-GlcNAc-modified proteins using 6-azido-6-deoxy-N-acetyl-galactosamine. Org Biomol Chem 17:4326-4334 (2019). Read more (PubMed: 30976765) »
  • Mitchell LA  et al. PD-L1 checkpoint blockade delivered by retroviral replicating vector confers anti-tumor efficacy in murine tumor models. Oncotarget 10:2252-2269 (2019). Read more (PubMed: 31040917) »
See all 27 Publications for this product


1-10 of 16 Abreviews or Q&A


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. getroffen. Ich kann Ihnen aber versichern, dass im Moment keine Pläne bestehen, diese Produkte aus dem Katalog zu nehmen.
Ich schlage vor diese vier Produkte zu testen. Wenn Sie Ihren Anforderungen entsprechen, besteht die Möglichkeit eine größere Menge (Bulk) zu bestellen. Diese kann auch als Lyophilisat geliefert werden und wäre somit für Jahre ohne Qualitätsverlust haltbar.
Ich hoffe, diese Information ist hilfreich und verbleibe

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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

提交于 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 of optimization to determine the optimal dilution to use in your ELISA, but I recommend starting at 1:10,000 or 1:15,000 fold dilution.

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

提交于 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.

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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 human I-309, but one is biotinylated, which allows the two rabbit antibodies to be used together in ELISA. Detection is achieved with an avidin or streptavidin enzyme conjugate such as the HRP -conjugated streptavidin ab7403.

Efficacy in ELISPOT is assumed to be likely if efficacy in standard sandwich ELISA has been demonstrated, but optimizing the amount of capture antibody and detection antibody will be necessary.

There are other pairs that might work but that have not been tested together for ELISA of any kind. For example, the mouse monoclonal ab89446 could be used for capture, followed by detection with a polyclonal antibody raised against full-length protein, such as the rabbit anti-I-309 ab109788 or the goat anti-I-309 ab10377, followed by an anti-rabbit IgG or anti-goat IgG secondary conjugate that has been absorbed/purified to remove reactivity with mouse IgG. Please note that our guarantee only applies to tested applications.

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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, this product should be stored in its undiluted form for maximum activity and only diluted prior to use. However, if you would like to re-order ab7403 to make aliquots of the undiluted protein, I could exceptionally give you a 50% discount off this product.

If you would like to re-order this product, please let me know by replying to this email.

I hope this information is helpful to you. Please do not hesitate to contact us if you need any more advice or information.

Free Rabbit monoclonal antibody with any purchase of a primary antibody, while stocks last! Quote “RABMAB-XBSMG” in your next primary antibody order. For more information, visit the following link: https://www.abcam.com/index.html?pageconfig=resource&rid=15447

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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 the diluted form, it will loose it's activity and therefore colour. This product must be stored at -20ºC ONLY in it's undiluted form and then kept at 4ºC in the undiluted form also when it is being used in ELISA. You should only dilute this protein prior to immediate use.

Undiluted protein will last several weeks at 4ºC but not longer than 2 months and the diluted protein is not stable at 4ºC for any period of time.

Since it is stated on the datasheet that this product should be aliquoted and stored at -20ºC upon delivery and makes no guarantees about its stability at 4ºC, the product is therefore not covered by our abpromise guarantee. I am going to look into your case and see if we can give you any discounts on a next order. In order to do this, could let let me know when you placed the original order and who placed it ?

I hope this information is helpful to you and I look forward to your response.

Free Rabbit monoclonal antibody with any purchase of a primary antibody, while stocks last! Quote “RABMAB-XBSMG” in your next primary antibody order. For more information, visit the following link: https://www.abcam.com/index.html?pageconfig=resource&rid=15447

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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.

Could you please clarify the details below:

1. Was sodium azide added to the aliquots before freezing?

2. Do you always keep your working aliquots at 4ºC for 3 weeks only?

3. Is the problem happening with the original lot of the protein which used to work fine?

4. Are you diluting the protein to the desired concentration and then storing at -20ºC?

If you are diluting the protein to the desired concentration and then storing at -20ºC or at 4ºC for immediate use then the Streptavidin Peroxidase conjugated will not be stable hence why the colour fades. This product is only stable in the undiluted form for a few weeks at 4° C. You should only dilute this protein prior to immediate use for optimal activity.

I hope this information is helpful to you and I look forward to receiving your reply.

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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 estimation of molarity [Moles/liter = Grams/[(grams/mole) X Liters]is 1.06 x 10-5mol/L.

I hope this information is helpful to you. Please do not hesitate to contact us if you need any more advice or information.

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