GSTrap HP 1-mL and 5-mL columns are prepacked with Glutathione Sepharose High Performance resin, which provides high-resolution purifications, thus a more concentrated sample. GST-tagged proteins are purified from pretreated bacterial lysates by affinity chromatography using immobilized glutathione, such as Glutathione Sepharose High Performance. GST-tagged proteins are bound to the affinity resin, and impurities are removed by washing with binding buffer