Learn how to use this product The 10x Buffer BXT is a 10x concentrated Strep-Tactin®XT elution buffer. It needs to be diluted before use. Biotin reversibly binds to Strep-Tactin®XT, which allows the elution of Strep-tag®II or Twin-Strep-tag® fusion proteins. It should be noted that biotin binds irreversibly to Strep-Tactin®. Therefore, 10x Buffer BXT is not suitable for elution of Strep-tag®II or Twin-Strep-tag® proteins from Strep-Tactin® resins since regeneration after use is not possible.