Streptavidin (SA) is produced by Streptomyces avidinii and isolated by purification from fermentation broth. The molecule of streptavidin consists of 4 identical subunits, each bearing an active binding site for the vitamin biotin.

  • High affinity – binds 4 moles of biotin per mole of protein
  • Fast reacting  – due to high affinity of the biotin-streptavidin interaction
  • Typically used in combination with biotinylated antibodies in order to obtain amplified signals detecting sub-nanogram amounts of antigen.
  • Can also be coated directly on the solid phase in the first step of an ELISA and used as a generic capture system for biotinylated antibodies with poor coating properties. Having plates pre-coated with streptavidin reduces the need for developing new coating methods.


  • BSA free
  • Free of azide, mercury or other toxic preservative formulations
  • White lyophilized powder
  • Lyophilized in 50 mM NaCl (pH 9.0)
  • Activity > 13 U/mg (one unit binds 1 μg of biotin)
  • Purity: SDS – 1 band (non-reduced)
  • Molecular weight: 55.000 Dalton
  • Ip: slightly acidic, 5-6


  • No detectable decomposition within 36 months when stored dry at -20°C
  • Stable over a wide range of pH and decomposes only in the presence of SDS > 60°C


All products are available as OEM components or under our own Kem-En-Tec Diagnostics A/S label.

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