Kinetic Parameters of GM-CSF Receptors at 23°C and 4°C
| . | Low-Affinity GM-CSF Receptor . | |||
|---|---|---|---|---|
| 23°C . | Mean Ratio . | 4°C . | Mean Ratio . | |
| kd | (15 ± 5.6) nmol/L | 1.1 | (14 ± 7.0) nmol/L | 1.0 |
| kon | (2.5 ± 1.3) × 10−6 pmol/L−1min−1 | 2.8 | (8.9 ± 2.7) × 10−7 pmol/L−1min−1 | 1.0 |
| koff | (5.5 ± 1.7) × 10−2 min−1 | 1.5 | (3.8 ± 1.0) × 10−2min−1 | 1.0 |
| High-Affinity GM-CSF Receptor | ||||
| 23°C | Mean Ratio | 4°C | Mean Ratio | |
| kd | (34 ± 5.2) pmol/L | 0.0025 | (234 ± 85) pmol/L | 0.017 |
| kon | (1.5 ± 0.27) × 10−4 pmol/L−1min−1 | 171 | (6.2 ± 1.8) × 10−5 pmol/L−1min−1 | 69 |
| koff (loose) | (4.5 ± 0.71) × 10−2 min−1 | 1.2 | (2.7 ± 0.24) × 10−2min−1 | 0.73 |
| koff (tight) | (2.1 ± 0.60) × 10−3 min−1 | 0.056 | (3.6 ± 0.32) × 10−3min−1 | 0.097 |
| . | Low-Affinity GM-CSF Receptor . | |||
|---|---|---|---|---|
| 23°C . | Mean Ratio . | 4°C . | Mean Ratio . | |
| kd | (15 ± 5.6) nmol/L | 1.1 | (14 ± 7.0) nmol/L | 1.0 |
| kon | (2.5 ± 1.3) × 10−6 pmol/L−1min−1 | 2.8 | (8.9 ± 2.7) × 10−7 pmol/L−1min−1 | 1.0 |
| koff | (5.5 ± 1.7) × 10−2 min−1 | 1.5 | (3.8 ± 1.0) × 10−2min−1 | 1.0 |
| High-Affinity GM-CSF Receptor | ||||
| 23°C | Mean Ratio | 4°C | Mean Ratio | |
| kd | (34 ± 5.2) pmol/L | 0.0025 | (234 ± 85) pmol/L | 0.017 |
| kon | (1.5 ± 0.27) × 10−4 pmol/L−1min−1 | 171 | (6.2 ± 1.8) × 10−5 pmol/L−1min−1 | 69 |
| koff (loose) | (4.5 ± 0.71) × 10−2 min−1 | 1.2 | (2.7 ± 0.24) × 10−2min−1 | 0.73 |
| koff (tight) | (2.1 ± 0.60) × 10−3 min−1 | 0.056 | (3.6 ± 0.32) × 10−3min−1 | 0.097 |
Data represent the results of at least three individual experiments. Mean ratios were normalized by dividing the mean measured kinetic constant by the corresponding value of the low-affinity GM-CSF receptor obtained at 4°C.