Buffer E is a Strep-Tactin® Elution Buffer with Desthiobiotin (10x concentrated) and used for elution of Strep-tag®II and Twin-Strep-tag® proteins from the biotin-binding site of Strep-Tactin® resins in a competitive manner resulting in a mild elution.
Do not use for elution from Strep-Tactin®XT resin!