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Protein purification with Strep-Tactin®

Strep-Tactin® allows affinity purification of Strep-tag®II and Twin-Strep-tag® fusion proteins under physiological conditions. In contrast to other tags, these mild purification parameters preserve bioactivity of the protein and the high specificity between Strep-tag ®II and Strep-Tactin ® can yield over 99% purity after a single chromatographical step. 

Strep-Tactin® is especially suitable for standard proteins with good expression rates and binding properties. Furthermore, Strep-Tactin® can be alternatively used for the purification of proteins where the binding to the high affinity variant Strep-Tactin®XT is too strong.

Strep-Tactin® purification cycle

Strep-Tactin® resin is used for the purification of Strep-tag®II or Twin-Strep-tag® proteins. Protein purification with Strep-Tactin® is straightforward and quick, as the purification cycle for each target protein remains consistent. Additionally, if a target protein requires a specific buffer composition, such as PBS, HEPES, or buffer free from chelating agents like EDTA, the buffers can be easily adapted without altering the purification cycle. Strep-Tactin® resin is compatible with various buffer compositions, reagents, and additives. A comprehensive list of compatible reagents can be found here.


 Binding affinity

 Strep-tag® II: μM range
 Twin-Strep-tag®: nM range


 Elution with Buffer E
 (2.5 mM Desthiobiotin)


 Regeneration with 100 mM NaOH

Key features of Strep-Tactin® protein purification

  • Purification of bioactive recombinant proteins under physiological conditions
  • Broad range of detergents, chelators, salt or redox conditions allowed 
  • Highly specific interaction of Strep-tag® with Strep-Tactin®, no unspecific protein binding (high specificity in screening and assays)

Find out more about Strep-tag® protein purification

Here, we have grouped links to make it easier to find more information about Strep-tag® technology for protein purification. In our web shop, you can find the protein purification products  that fit your research needs. Read the comprehensive comparison of the most used tag systems, Strep-tag® vs. His-tag. Browser through application examples and frequently asked questions about Strep-tag® purification system or download application notes in our download area.