Desthiobiotin is a modified form of biotin that displaces Strep-tag®II and Twin-Strep-tag® fusion proteins from the modified biotin-binding pocket of Strep-Tactin® in a competitive manner, resulting in a mild elution. Desthiobiotin powder can be used for preparation of Strep-Tactin® elution buffer, Buffer E. Please note that desthiobiotin is not applicable for elution from Strep-Tactin®XT resins.