Streptavidin Protein

Streptavidin Protein

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  • Streptavidin Protein

  • Streptavidin
  • PRO-283
  • Shipped at Room temp.

Catalogue number



Streptavidin is a tetrameric protein secreted by Streptomyces avidinii which binds firmly to biotin. Streptavidin is wilyde used in molecular biology through its unique high affinity for the vitamin biotin. The dissociation constant (Kd) of the biotin-streptavidin complex is about ~10-15 mol/L. The strong affinity recognition of biotin and biotinylated molecules has made streptavidin one of the most important components in diagnostics and laboratory kits. The streptavidin/biotin system has one of the biggest free energies of association of yet observed for noncovalent binding of a protein and small ligand in aqueous solution (K_assoc = 10**14). The complexes are also extremely stable over a wide range of temperature and pH.


Streptavidin is a protein produced by Streptomyces avidinii and isolated by purification from fermentation broth. The pure, homogeneous protein shows predominantly one single band in SDS PAGE. Streptavidin consists of 4 identical subunits, each bearing an active binding site for biotin. Streptavidin has a molecular weight of 55kDa.


Bacterium Streptomyces avidinii.

Physical Appearance

Sterile Filtered lyophilized powder.


The Streptavidin was lyophilized from a 25mg/ml solution in 10 mM potassium phosphate buffer pH 6.5


Gives a clear solution at 5mg/ml in 0.1M NaCl.


Streptavidin although stable at 4°C for 3 weeks, should be stored desiccated below -18°C.
For longer storage in dissolved form add 1mM EDTA and/or 0.02 % NaN3 or pass the solution through a sterile filter.
Please prevent freeze-thaw cycles.

Specific Activity

The biological activity is 16.8 U/mg, 1 unit binds 1µg biotin.

Safety Data Sheet


ProSpec's products are furnished for LABORATORY RESEARCH USE ONLY. The product may not be used as drugs, agricultural or pesticidal products, food additives or household chemicals.


Streptavidin Recombinant: A Versatile Tool for Biotechnology and Biomedical Research



Streptavidin Recombinant: A Versatile Tool for Biotechnology and Biomedical Research



Streptavidin is a widely used protein in biotechnology and biomedical research due to its exceptional binding affinity to biotin. This section introduces streptavidin and highlights its significance as a versatile tool in various applications.


Molecular Structure of Streptavidin

This section explores the molecular structure of streptavidin, including its tetrameric arrangement and the unique binding pocket for biotin. The structural features of streptavidin are crucial for understanding its robust binding properties and engineering modifications.


Binding Mechanism of Streptavidin and Biotin

The interaction between streptavidin and biotin is one of the strongest noncovalent interactions known in nature. This section explains the binding mechanism in detail, emphasizing the tight and specific association between streptavidin and biotin molecules.


Applications of Streptavidin in Biotechnology

Streptavidin's high affinity for biotin makes it an invaluable tool in various biotechnological applications. This section discusses the utilization of streptavidin in techniques such as affinity chromatography, protein purification, immunoassays, and biotinylation strategies.


Streptavidin-Based Detection Systems

Streptavidin is widely employed in detection systems, including enzyme-linked immunosorbent assays (ELISAs), Western blotting, and immunohistochemistry. This section explores the use of streptavidin-conjugated enzymes or fluorophores for sensitive and specific detection of target molecules.


Streptavidin in Bioimaging and Nanotechnology

Streptavidin's exceptional binding affinity has paved the way for its applications in bioimaging and nanotechnology. This section discusses the use of streptavidin in fluorescence imaging, nanoparticle conjugation, and the development of biosensors.


Streptavidin as a Tool for Drug Delivery

Streptavidin can be harnessed for targeted drug delivery strategies. This section explores the conjugation of streptavidin with therapeutic agents and the use of biotinylated targeting ligands for site-specific drug delivery.



Streptavidin recombinant is a versatile tool that plays a vital role in biotechnology and biomedical research. Its strong binding affinity for biotin enables a wide range of applications, from protein purification to bioimaging and drug delivery

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