Learn how to use this product The Strep-Tactin® conjugated with horseradish peroxidase (HRP) enables fast and targeted detection of Strep-tag®II or Twin-Strep-tag® fusion proteins. Target proteins can be transferred to a blotting membrane or captured on a microplate before chromogenic or chemiluminescence detection using Strep-Tactin® HRP. Depending on the host organism, protein extracts may contain small amounts of biotinylated proteins. To prevent false positive bands, a Biotin Blocking Buffer is recommended for blocking such biotinylated proteins on western blots prior to detection. Biotin Blocking Buffer contains the tetrameric biotin-binding protein avidin, which also selectively binds biotinylated proteins.