Learn how to use this product The Strep-Tactin®XT 4Flow® high-capacity columns are well-suited for the purification of Strep-tag®II or Twin-Strep-tag® fusion proteins via gravity flow. The column is recommended for proteins of all classes, especially low abundant, large, and highly expressed proteins, due to its pH compatibility, target purity (>95%), and high binding affinity. Strep-Tactin® resins are recommended for multimeric protein complexes, as they might bind too strongly to the Strep-Tactin®XT 4Flow® high-capacity resins, preventing efficient elution. Denaturing agents such as urea can be used with Strep-Tactin®XT 4Flow® high capacity. In comparison to Strep-Tactin®XT 4Flow®, Strep-Tactin®XT 4Flow® high capacity has a higher density of immobilized Strep-Tactin®XT, which leads to a higher yield of purified protein. For the fast purification of large samples, the WET FRED system (IB 2-0910-001) is recommended.