Biotin Blocking Buffer

Depending on the host organism, protein extracts may contain small amounts of biotinylated proteins such as the biotin carboxyl carrier protein (BCCP, 22 kDa) of E. coli. Biotin Blocking Buffer is recommended for blocking such biotinylated proteins on western blots prior to detection of Strep-tag®II or Twin-Strep-tag® fusion proteins with Strep-Tactin® or Strep-Tactin®XT conjugates to prevent the detection of false positive bands. The buffer contains the tetrameric biotin binding protein avidin, which selectively binds biotinylated proteins. Please note that usage of Biotin Blocking Buffer is not necessary when using StrepMAB-Classic, since this antibody does not bind to biotinylated proteins.