Fig. 5. In vitro pull-down of POMC-derived peptides by GST-CPE, GST-SgIII and GST-CgA. The GST-fused proteins, SgIII 23-471, CgA 1-448 and CPE 23-477 (20 µg each), were immobilized on glutathione beads and incubated with AtT-20 cell extract (1.0 ml) for pulling down POMC-derived peptides. For GST pull-down control, although GST alone did not bring down POMC-derived peptides, GST-7B2 27-210 was used as a negative control to show that particular SG-residential proteins are able to bring down POMC-derived peptides. POMC-derived peptides in the pulled-down precipitates were analyzed by SDS-PAGE and immunoblotting using the antibody to ACTH. One-twentieth of the cell extract was run on lane 5 (n=5).