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.
Biotin Blocking Buffer (2-0501-002) for western blotting can be prepared by dissolving 2.5 mg/ml Avidin in PBS buffer.
Form: | Powder |
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Possible Application: | Blocking of biotin in e.g. culture media |
Size: | 17 kDa per subunit |
Source: | Egg white |
Specific Activity: | > 11 U/mg |
Storage: | 2-8 °C |
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Stability: | 12 months after shipping |
Shipping: | Room temperature |