Table 2.

Effect of IGFBP‐3 modifications on its binding to HA or HN. IGFBP‐3 (50 nm) was bound to the ELISA plate wells, and then, 0–2 μm biotin‐HA or biotin‐HN was added and processed as described in the Materials and methods section. The blank containing all components but without biotin‐HA or biotin‐HN was subtracted from all values; then, the optical density was normalized by expressing each point in relation to the best‐fitted Emax value (set to 100%). The concentration of biotin‐HA or biotin‐HN (nm) that produced 50% of maximum binding is shown as the mean ± SD of three independent experiments, each run in triplicate. Controls included samples that were alkylated without prior reduction.

	IGFBP‐3 Nonglycosylated	IGFBP‐3 Glycosylated	IGFBP‐3 Nonglycosylated/Reduced	IGFBP‐3 Glycosylated/Reduced
Biotin‐HA	182 ± 32	180 ± 28	176 ± 26	190 ± 28
Biotin‐HN	92 ± 16	104 ± 14	96 ± 12	98 ± 16