Avidin is a tetrameric biotin binding protein (KD ~1 x 10-14) extracted from egg white. It prevents biotin and biotinylated proteins from binding to Strep-Tactin® or Strep-Tactin®XT, whereas binding of the Twin-Strep-tag® and Strep-tag®II is not influenced. Biotin and/or biotinylated proteins can potentially reduce the binding capacity of Strep-Tactin® as well as Strep-Tactin®XT and are present in cell lysates and cell culture media, especially from mammalian or insect cells. Thus, if Twin-Strep-tag® and Strep-tag®II fusion proteins from biotin-containing extracts or media are intended to be purified via Strep-Tactin® or Strep-Tactin®XT affinity chromatography, biotin has to be masked by addition of avidin prior to application onto the resin.
Specifications
- Form: Powder
- Possible Application: Blocking of biotin in e.g. culture media
- Size: 17 kDa per subunit
- Source: Egg white
- Specific Activity: > 11 U/mg
