Strep-Tactin®XT Buffer Set contains all buffers necessary for purification of Strep-tag®II or Twin-Strep-tag®
fusion proteins with Strep-Tactin®XT as well as for subsequent regeneration of the resin. Buffer W (10x) is a 10x concentrated wash buffer for Strep-Tactin® and Strep-Tactin®XT
resins. It removes unbound molecules from the affinity chromatography matrix during Strep-tag®II and Twin-Strep-tag® fusion protein purification. Buffer BXT (10x) is a 10x concentrated Strep-Tactin®XT elution buffer containing biotin. Biotin is a water-soluble B-complex vitamin, also known as vitamin B7 or vitamin H. It binds to Strep-Tactin®XT with very high affinity but reversibly and, thereby, allows the efficient elution of Strep-tag®II or Twin-Strep-tag® fusion proteins from the resin.
Please note that Buffer BXT (10x) is not applicable for elution of Strep-tag®II or Twin-Strep-tag® fusion proteins from Strep-Tactin®, since biotin irreversibly binds to these resins, and, thus, Strep-Tactin® cannot be regenerated.
Buffer XT-R is a ready-to-use Strep-Tactin®XT regeneration buffer containing magnesium chloride for competitive displacement of biotin from the modified biotin-binding pocket of Strep-Tactin®XT after the elution of Strep-tag®II or Twin-Strep-tag® fusion proteins.
Please note that the Strep-Tactin®XT Buffer Set is not applicable for Strep-Tactin®.