oYo-Link® His12 Tag

Site-specifically label your antibody with oYo-Link His-12 Tag for antibody immobilization on Transition Metal (e.g. Ni ²⁺, Co ²⁺ ) coated surfaces.

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oYo-Link® His12 Tag uses a His12 Tag for the immobilization of compatible antibodies on Transition Metal (e.g. Ni ²⁺, Co ²⁺ ) coated surfaces. Proper antibody orientation thanks to site-specific immobilization can improve sensitivity, stability and longevity of capture antibodies, with up to a >10-fold increase in sensitivity for ELISA through enabling increased antigen capture per unit area.

Requirements: Photo-Crosslinking Device

Quote or Bulk Orders? Request a quote here.





For research use only.

oYo-Link® His12 Tag is recommended for the immobilization of antibodies on Transition Metal (e.g. Ni ²⁺, Co ²⁺ ) coated surfaces (or coated w/ other His-binding proteins). oYo-Link® His12 Tag enables the site-specific labeling of oYo-Link®-compatible antibodies with a His12 tag to the IgG heavy chain. The use of a single His12 Tag maximizes mobility and antigen binding density of surface-immobilized antibodies.

Site-specific immobilization can lead to an improvement in sensitivity, stability and longevity of capture antibodies.

While the magnitude of improvement is dependent on various parameters, such as antibody binding properties, uniform antibody orientation on a surface can lead to a > 10-fold increase in sensitivity in enzyme-linked immunosorbent assays (ELISA) by enabling the capture of more antigens per unit area.


Applications: Conjugation of capture antibodies with His12 Tag for Transition Metal (e.g. Ni 2+, Co 2+) -Coated Surface Immobilization in Direct-ELISA; not recommended for Sandwich-ELISA. Also for Reactions with other His-reactive Groups.


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.


Purchasing Information: For Credit Card purchases, proceed with checkout on website. To request a quote click here.


Technical Support: For additional questions concerning compatibility please contact us 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

oYo-Link® His Tag Antibody Crosslinking Data

oYo-Link His-12 Tag Photo-crosslinking Efficiency shown by SDS-PAGE: using a 4-12% Tris Gel shows an upwards shift of the antibody heavy chain following site-specific photo-crosslinking with oYo-Link.

*Note the size and migration for each unreacted oYo-Link product will differ.

Please Note You can label as little as 1 µg of Antibody at a time.

Catalog Amount Labeled Price(USD) Spec Sheet
AT2002-25 Label 25 µg Antibody $100 Download Here
AT2002-100 Label 100 µg Antibody $300 Download Here
AT2002-mIgG1-100 Label 100 µg mouse IgG1 Antibody $300 Download Here
AT2002-500 Label 500 µg Antibody $1050 Download Here
AT2002-mIgG1-500 Label 500 µg mouse IgG1 Antibody $1050 Download Here
AT2002-1000 Label 1000 µg Antibody $1500 Download Here
AT2002-mIgG1-1000 Label 1000 µg mouse IgG1 Antibody $1500 Download Here


Product Name

oYo-Link® His-12 Tag

Catalog #


Lot #

See Product Spec Sheet shipped with product

Antibody and Buffer Compatibility

See oYo-Link Antibody & Buffer Compatibility Table here

Molecular Weight

8000 g/mol


270 µg/mL

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 (less than 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. If you are interested in our conjugation service, please contact us at support@alphathera.com. For custom conjugation services, you will need to send us your antibody. The conjugation and purification fee depends on the size and specifications of each order. Purification is not required for most applications.

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.

  • Proper Antibody Orientation on Surface
    Uniform Antibody orientation maximizes the antigen binding density of the surface -immobilized antibodies. Site-specific, covalent labeling of an antibody’s Fc region only, with no impact on antibody binding. Read Why Site-Specific is Better.
  • Improved Assay Sensitivity
    Proper antibody orientation can improve sensitivity, stability and longevity of capture antibodies. This can result in up to 10x increase in ELISA sensitivity by enabling the capture of more antigens per unit area.
  • Rapid & Efficient Labeling
    Reactions require less than  30 seconds hands-on time, 2 hours total. Labeling is highly efficient, resulting in highly homogeneous products with one-to-two labels per antibody.
  • Robust Antibody & Buffer Compatibility
    Works with nearly all antibody species and subclasses. Reactions are insensitive to all common buffers, a wide range of pH values, and the presence of storage proteins (e.g. BSA).