oYo-Link® HRP

Rapid, site-specific labeling of primary antibodies with HRP. Highly uniform conjugates, no optimization required.

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oYo-Link® Horseradish Peroxidase (HRP) Antibody Labeling

Research Use Only.

oYo-Link® HRP enables the rapid production of highly uniform primary antibody-HRP conjugates in under 2 hours, with only 30 seconds hands-on time. Site-directed conjugation of 1-2 HRP labels to the heavy chain of compatible primary antibodies ensures consistent conjugates that do not require optimization. Simply mix the oYo-Link® HRP with your antibody and then illuminate using our LED Photocrosslinking device.

Requirements: Photo-Crosslinking Device

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oYo-Link® HRP allows rapid direct conjugation of compatible antibodies to HRP for a wide range of applications including ELISA, Western blotting and IHC.

Using directly labeled primary antibodies is a preferred detection method for these applications because of the many wash steps required in indirect detection, as well as the cross-species reactivity that can occur with the use of secondary antibodies. However labeling primary antibodies can be complex and time consuming.

oYo-Link® HRP allows researchers to directly conjugate their antibody to HRP, so there is no need for secondary antibodies. Furthermore, the labeling procedure is rapid and requires only 30 seconds hands-on time, with conjugates ready within 2 hours. The researcher simply has to mix their antibody with oYo-Link HRP and then illuminate for 2 hours using our LED Crosslinking device. oYo-Link is compatible with all common storage buffers so there is no need to purify or desalt your antibody prior to labeling. (see Buffer Compatibility Table)

oYo-Link® also enables site-specific labeling of the antibody heavy chain only. This ensures uniform labeling of 2 HRP labels per antibody, producing consistent antibody-HRP conjugates that require no further optimization steps, therefore saving time and cost.

Applications: Western Blotting, ELISA, IHC

Requirements: To label your compatible antibodies with oYo-Link®, you will need a light source emitting at 365nm (6-10W). Purchase AlphaThera’s LED Photo-Crosslinking Device here, or use a compatible device.

Placing an order: For credit card purchases, proceed with checkout on website. To request a quote click here.

Technical Support: For any technical questions please contact our technical support team here.

Webinar: Simple, fast, site-specific antibody labeling with oYo Link®

Watch our short introduction to AlphaThera’s oYo-Link® site-specific antibody conjugation technology and learn how to streamline your assays with these superior labeling products.

Antibody Conjugation User Manual

Read our antibody conjugation usual manual for instructions on how to easily conjugate your antibody with oYo-Link products.

Demo: oYo-Link® Antibody Conjugation

Find out how to site-specifically label your antibody with just two steps: mix and illuminate. 30 seconds hands-on time, 2 hours total.

oYo-Link® Product Brochure

Download our product brochure

Immunohistochemistry data: Anti-vimentin antibody (Cat #: MAB21052) was conjugated to HRP and stained human testis tissue. Staining is confined to cytoplasm of sperm cells.

ELISA of Primary antibody-oYo-Link HRP vs Primary antibody + 2nd antibody-HRP comparison. The results show the ELISA assay sensitivity of anti-BSA Rabbit IgG labeled with oYo-Link HRP equals to primary antibody combined with 2nd goat anti-Rabbit IgG-HRP.

Catalog Amount Labeled Price(USD) Spec Sheet
AT6002-100 Label 100 µg Antibody $350 Download Here
AT6002-mIgG1-100 Label 100 µg mouse IgG1 Antibody $350 Download Here
AT6002-500 Label 500 µg Antibody $1250 Download Here
AT6002-mIgG1-500 Label 500 µg mouse IgG1 Antibody $1250 Download Here
AT6002-1000 Label 1000 µg Antibody $1875 Download Here
AT6002-mIgG1-1000 Label 1000 µg mouse IgG1 Antibody $1875 Download Here


Product Name

oYo-Link® Horseradish Peroxidase (HRP)

Catalog #


Lot #

See Product Spec Sheet shipped with product

Antibody and Buffer Compatibility

See oYo-Link Antibody & Buffer Compatibility Table here.

Molecular Weight




Molar Concentration

33 µM

Storage Buffer

1 x PBS

Shipping Condition

This product is shipped as a dried clear or white pellet at ambient temperature.


Before opening, briefly centrifuge each tube to ensure that the entire pellet is at the bottom. For all product tubes: Add 100 µL sterile ddH2O and vortex tube briefly until fully dissolved.

Storage and Stability

The dried product can be stored at 4°C or -20°C upon receipt. Following reconstitution, the product can be stored at 4°C for short-term durations (< 1 week) and -20°C to -80°C for longer time-spans.

Conjugation Instructions

After reconstitution, each product tube is capable of labeling up to 100 µg of antibody. Please find and follow the Antibody Conjugation User Manual here.

Other Notes

Disposal of product should be performed in compliance with all applicable federal, state, and local regulations. This product does not meet hazard classification criteria based on evaluations made by our company under the OSHA Hazard Communication Standard, 29 CFR 1910.1200.

Will oYo-Link work with my antibody?

Please check the antibody compatibility table. Note: oYo-Link mIgG1 can be used to label mouse IgG1 antibody. Currently, oYo-Link mIgG1 is only available for certain products. Please check the product webpage. oYo-Link mIgG1 only labels mouse IgG1 and is not compatible with other antibodies.

Can oYo-Link be used to label antibodies in the presence of albumin and/or Tris?

Yes, since oYo-Link specifically bind to the heavy chain of IgG, it works in the presence of both albumin and Tris. oYo-Link is compatible with all common buffers. See the full buffer compatibility table here.

If an oYo-Link product has accidentally been left at room temperature for a week, will it still work?

With the exception of oYo-Link DBCO, all oYo-Link products are shipped as white or clear pellets and are very stable. While we recommend cold storage, they will not exhibit any loss of activity if left at room temperature for a week. oYo-Link DBCO must be shipped and stored cold (-20°C) immediately upon arrival, otherwise there will be a loss in activity.

Does AlphaThera offer conjugation service?

Yes. You can find more information about our conjugation services here.

How many oYo-Link labels will be conjugated to each antibody?

For most subclasses and species of antibody, oYo-Link will result in the conjugation of 2 labels per antibody (maximum), one label per heavy chain. For example, ~95% of human IgG and Rabbit IgG will have two labels per antibody. However, there are a few antibodies such as mouse IgG2b and goat IgG, where the conjugation is slightly less efficient. In this case, 60 to 80% of the antibody will be labeled and have a mixture of 0, 1 and 2 labels per antibody. See the antibody conjugation efficiency here

How do I know if oYo-Link was successfully conjugated to my antibody?

Antibody conjugation can be checked on SDS-PAGE gel. An example is present in the supporting data on each product page.

Does 365nm UV illumination damage the antibody and its binding affinity?

The conjugated and unconjugated antibody binding affinities have been tested via both ELISA and cell binding assays and don’t show any difference.

Do I need to remove free oYo-Link after conjugating to antibody?

For most immunoassay applications, purification is not necessary. In our standard recommended protocol, the molar ratio of oYo-Link-to-antibody is 5:1. These conditions ensure that the antibody conjugation efficiency reaches its maximum; however there will be a slight excess remaining in your antibody mixture. This is usually removed during immunoassay washing steps. However, if your application requires high antibody-conjugate purity, please contact us for more information on this process and for a detailed protocol.

For oYo-Link click-chemistry products, should I perform the click reaction before conjugation?

When working with oYo-Link Azide (Catalog #: AT3002) and oYo-Link DBCO (Catalog #: AT3003), it is required to perform the click chemistry coupling reactions with the molecule of interest first, prior to photo-crosslinking to an antibody. This is to avoid UV illumination damage to the click moiety and to avoid diluting oYo-Link prior to the reaction to maximize the reaction efficiency. For oYo-Link Tetrazine (Catalog #: AT3004) and oYo-Link Thiol (Catalog #: AT3001); it is recommended to perform the coupling reaction before photo-crosslinking. This is to avoid diluting oYo-Link prior to the coupling reaction to maximize the reaction efficiency.

What is the lowest amount of antibody that can be labeled by oYo-Link reagents?

We recommend working with at least 1 µg of antibody; however, it is possible that even lower amounts of antibody can be labeled.

Can antibodies that are highly dilute be labeled by oYo-Link reagents?

Yes, antibodies can be efficiently labeled even if diluted to concentrations as low as 50 µg/mL.


  • Rapid & easy labeling, only 30 seconds of hands-on time, 2 hours total conjugation.
  • Label primary antibodies for direct detection, avoid laborious wash steps and cross-species reactivity.
  • Site-specific labeling at the antibody Fc region guarantees no interference with the antigen binding site.
  • Site-specific labeling ensures the production of highly consistent conjugates with no requirement for further optimization.
  • Label from as little as 1 µg and work with antibody concentrations as low as 50 µg/mL. No need to concentrate or centrifuge your sample prior to labeling.
  • Compatible with all common buffers – no need for antibody purification.