Table 1.
Relative binding affinities (in %) of individual ligands for individual receptors and binding proteins.
| Hormone | Receptor Relative binding affinity (%) | ||||||
|---|---|---|---|---|---|---|---|
| IR-A | IR-B | IGF1R | M6P/IGF2R:D11 | M6P/IGF2R | IGBP3 (binary complex) |
IGFBP3:ALS (ternary complex) |
|
| IGF2 | 8.5 ± 3.8 | 3.6 ± 1.8 | 15.8 ± 3.6 | 100 ± 30 | 100 ± 40 | 100 ± 71 | 100 ± 45 |
| IGF1 | 1.1 ± 0.4 | 0.11 ± 0.03 | 100 ± 47 | no binding | 4.0 ± 1.2 | 65 ± 35 | n.d. |
| HI | 100 ± 31 | 100 ± 37 | 0.08 ± 0.03 | n.d. | n.d. | n.d. | n.d. |
| big-IGF2(87) | 7.1 ± 1.6 | 2.7 ± 1.2 | 14.8 ± 7.1 | 73 ± 34 | 227 ± 119 | 70 ± 53 | 58 ± 40 |
| big-IGF2(104) | 9.8 ± 2.4 | 2.9 ± 1.2 | 9.7 ± 3.4 | 698 ± 295 | 887 ± 309 | 146 ± 73 | 17.0 ± 6.2 |
| pro-IGF2(156) | 2.2 ± 0.6 | 1.6 ± 0.6 | 0.35 ± 0.18 | 56 ± 42 | 20 ± 16 | 16.0 ± 11.3 | 9.1 ± 3.9 |
| gly pro-IGF2(156) | 2 | n.d. | 0.2 | n.d. | <1 | 18 | n.d. |
Relative binding affinities were calculated as (Kd of the native hormone/Kd of analog) × 100 (%). The experimental Kd values are provided in ESI. The statistical evaluation of data is shown in Fig. 3. n.d. is not determined. gly means glycosylated. Data on gly pro-IGF2(156) were obtained from only one measurement due to the small amount of material available.