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Immobilization of your Strep-tag® fusion protein


  • Antibody or serum screening
  • Diagnostic assays
  • Protein biochemistry
  • Protein kinetics
  • Protein interaction studies
  • Screening of engineered enzymes
  • Drug screening
  • Biacore

Benefits of Strep-tag® based immobilization

  • Oriented immobilization of recombinant proteins with N-terminal, C-terminal or internal Strep-tag®II/Twin-Strep-tag®
  • Effective screening procedures
  • Minimal non-specific binding
  • High and constant activity
  • Minimal coefficients of variation (cv)
Twin-Strep-tag Capture Kit (SPR)
The Twin-Strep-tag Capture Kit enables the highly stable immobilization of the ligand based on IBA´s unique Strep-Tactin®XT:Twin-Strep-tag® system, due to the pM affinity of Twin-Strep-tag® to Strep-Tactin®XT. In the Twin-Strep-tag® Capture Kit you get all necessary reagents and a protocol for the generation of Strep-Tactin®XT (capture molecule) coated sensor chips to immobilize Twin-Strep-tag® fusion proteins (ligand) efficiently.
Key benefits of Strep-Tactin®XT and Twin-Strep-tag® for SPR experiments
  • High affinity enables long term measurements (high affinity in low pM range; T1/2 = 13 h)
  • Chip can be easily regenerated
Strep-Tactin®XT coated microplates

Strep-Tactin®XT: Xtra Tight (pM affinity) immobilization of Twin-Strep-tag® fusion proteins

Ready-to-use microplates (12 x 8-well strips) for diagnostic/assay applications, coated with Strep-Tactin®XT, a further developed Strep-Tactin® variant with higher affinity for Strep-tag®II fusion proteins (binding affinity in nM range) and especially Twin-Strep-tag® fusion proteins (binding affinity in pM range). They are selectively captured from complex mixtures and the biomolecules of interest are presented to interaction partners in a uniform manner which results in reliable and reproducible assays. The solid-phase, multi-well format for convenient assays and high throughput screenings is compatible with standard multichannel pipettes and automated plate washers and plate readers.

Note that the bound fusion protein can still be eluted from the microplate.

Develop your own Assay!

Due to the high binding affinity of Strep-Tactin®XT with Twin-Strep-tag® in the low pM range, it is highly suitable for assays like SPR (surface plasmon resonance).

Request unconjugated Strep-Tactin®XT by using this form:

Strep-Tactin®XT request


Strep-Tactin® coated microplates
Strep-tactin coated 8-well strips and 96-well plates
Microplate consisting of twelve 8-well strips
coated with Strep-Tactin®

Ready-to-use Strep-Tactin® coated 8-well strips provide the power of our Strep-tag® system in a solid-phase, multi-well format for convenient assays and high throughput screenings of biomolecules tagged with Strep-tag®II. The strips are supplied framed in sets of 12, resulting in a 96-well configuration compatible with standard multichannel pipettes and automated plate washers and plate readers. The biomolecules are presented to interacting partners in a uniform manner, which results in reliable and reproducible assay formats.

StrepMAB-Immo (Ab)

High-affinity Strep-tag®II/Twin-Strep-tag® specific monoclonal antibody for capturing Strep-tag® fusion proteins on solid phases

• optimal for capturing Strep-tag® fusion proteins on solid phases (e.g. Biacore chips1)
• high affinity both with C- and N-terminal Strep-tag® fusion, provided the Strep-tag® is N-terminally extended by a SerAla-linker

1For more information on Biacore applications refer also to http://www.biacore.com/lifesciences/.


StrepMAB-Immo is a murine, high-affinity Strep-tag®II specific monoclonal antibody which is especially suited for stable, mild and oriented capturing of Strep-tag®II fusion proteins on solid phases. To realize this, the antibody can be immobilized on e.g. microplates, Biacore CM5 sensor chips or other biochips. The nearly irreversible binding is achieved both for fusion proteins carrying a C- or N- terminal Strep-tag®. The Strep-tag® must be N-terminally extended by a SerAla linker (recombinant protein - SA-WSHPQFEK or SA-WSHPQFEK - recombinant protein).


One of the most widely employed immobilization partners is avidin (66–69 kDa tetrameric glycoprotein) and biotin (water-soluble vitamin B). Avidin (Streptavidin) binds to biotin via an exceptionally strong non-covalent interaction. The binding interaction is rapid and nearly insensitive to pH, temperature, proteolysis, and denaturing agents. Biotin is a small molecule and conjugation to proteins does not significantly affect protein functionality or conformation.

Natural avidin or engineered avidin (e.g., streptavidin, neutravidin, and nitrividin) can be physisorbed or covalently linked to a surface for subsequent immobilization of biotinylated proteins.