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This buffer set contains all buffers necessary for purifying Strep-tag®II or Twin-Strep-tag® fusion proteins with Strep-Tactin®XT and subsequent resin regeneration. The kit contains 10x Buffer W, 10x Buffer BXT, and Buffer XT-R.
10x Buffer W 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. 10x
Buffer BXT 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 a very high affinity but reversibly, so Strep-tag®II or Twin-Strep-tag® proteins can be eluted efficiently from resins.
It should be noted that 10x Buffer BXT is not applicable for elution from Strep-Tactin® resins since biotin irreversibly binds to these resins and Strep-Tactin® cannot be regenerated.
Buffer XT-R is a ready-to-use Strep-Tactin®XT regeneration buffer containing magnesium chloride for the 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®.