FIGURE 3.

Competition binding curves of glycosylated IGF-II isoforms to purified IGFBP-2 (A), IGFBP-3 (B), and IGFBP-5 (C). Increasing amounts of each ligand were incubated in complex with 10 ng of purified IGFBP and 100,000 counts of Eu-IGF-II. The complexes were trapped on antibody-coated plates, and TRF was measured. The results are expressed as percentages of the TRF measured for Eu-IGF-II·IGFBP complex in the absence of competitor and are expressed as the means ± S.E. ■, IGF-II; □), glycosylated 1–156; ▴, glycosylated 1–104; ▵, glycosylated 1–87.