IC50 Values for Reciprocal Competition Experiments
| Receptor Fragment . | Radiolabeled Ligand . | IC50 of Unlabeled Competitor (nmol/L) . | ||
|---|---|---|---|---|
| Lactoferrin . | PAI-1 . | RAP . | ||
| E4-C10 | Lactoferrin | — | 766 ± 45 | 4.69 ± 1.33 |
| PAI-1 | 71 ± 3 | — | 2.03 ± 0.46 | |
| RAP | 143 ± 20 | 107 ± 21 | — | |
| C5-C7 | Lactoferrin | — | 280 ± 24 | 5.90 ± 1.63 |
| PAI-1 | 68 ± 10 | — | 1.69 ± 0.18 | |
| RAP | 352 ± 48 | 123 ± 11 | — | |
| Receptor Fragment . | Radiolabeled Ligand . | IC50 of Unlabeled Competitor (nmol/L) . | ||
|---|---|---|---|---|
| Lactoferrin . | PAI-1 . | RAP . | ||
| E4-C10 | Lactoferrin | — | 766 ± 45 | 4.69 ± 1.33 |
| PAI-1 | 71 ± 3 | — | 2.03 ± 0.46 | |
| RAP | 143 ± 20 | 107 ± 21 | — | |
| C5-C7 | Lactoferrin | — | 280 ± 24 | 5.90 ± 1.63 |
| PAI-1 | 68 ± 10 | — | 1.69 ± 0.18 | |
| RAP | 352 ± 48 | 123 ± 11 | — | |
IC50 values were calculated from the competitive binding curves shown in Fig 6 and from additional experiments performed with 125I-PAI-1. LRP fragment E4-C10 or C5-C7 was immobilized in microtiter wells and incubated with an iodinated ligand and increasing concentrations of the indicated unlabeled protein. Values represent the mean and SD of three separate experiments.