Purification of LCN2. (A) Recombinant GST-LCN2 was purified from E. coli BL21 by affinity chromatography using glutathione-sepharose 4B. Lysates from different purification steps were separated by SDS-PAGE: before (Bf) and after (Af) IPTG induction, supernatant after centrifugation (S), flow-through from column after loading supernatant (FT), 1st column wash (W1), 2nd column wash (W2), and elution of GST-LCN2 (E). (B) GST-LCN2 was digested by thrombin to remove the GST tag. GST-LCN2 was incubated with Thrombin-agarose (Sigma) at RT for up to 4 h. After 4 h incubation, the cleaved GST was absorbed by glutathione-sepharose. The supernatant containing only LCN2 (4 h*) was collected.