Glutathione Beads 4FF is an affinity chromatography medium designed for the purification of glutathione S-transferase (GST)-tagged proteins produced using the pGEX series of expression vectors, other glutathione S-transferases and glutathione binding proteins. The glutathione ligand is coupled to highly cross-linked 4% agarose beads. The coupling is optimized to give high binding capacity for GST-tagged proteins and other glutathione binding proteins. Glutathione Beads 4FF can purify GST-tagged proteins under high flow rate. Its high flow properties make it excellent for scale-up. The characteristics of Glutathione Beads 4FF are summarized in Table 1 . GSTCap 4FF is one of a range of prepacked, ready-to-use columns for affinity chromatography. It is packed with 1 ml and 5 ml of Glutathione Beads 4FF. Five different packing sizes are available. GSTCap 4FF has the standard interface and can be adapted to all kinds of chromatography system, such as ÄKTA. It is fast, simple and easy operation.