Western blot using affinity purified anti-NAG-1/GDF15 (C-terminal) antibody shows detection NAG-1 purified from CHO cells as a 14 kDa band corresponding to monomer and a 28 kDa band corresponding to dimerized NAG-1. Samples were electro-phoresed on a 4-20% gradient gel under reducing conditions. Lane 1 shows NAG-1 detection. Lane 2 shows reactivity is blocked when this antibody is pre-incubated with the immunizing peptide prior to Western blotting.