Kinetic parameters of the hydrolysis of FIX by IgG of patients with acquired hemophilia
| No. of patients . | Vmax, nM/min . | Km, μM . |
|---|---|---|
| 16 | 0.82 ± 0.19 | 7.26 ± 3.99 |
| 23 | 0.41 ± 0.03 | 0.94 ± 0.25 |
| 32 | 0.30 ± 0.03 | 1.81 ± 0.61 |
| Mean | 0.51 ± 0.08 | 3.34 ± 1.62 |
| No. of patients . | Vmax, nM/min . | Km, μM . |
|---|---|---|
| 16 | 0.82 ± 0.19 | 7.26 ± 3.99 |
| 23 | 0.41 ± 0.03 | 0.94 ± 0.25 |
| 32 | 0.30 ± 0.03 | 1.81 ± 0.61 |
| Mean | 0.51 ± 0.08 | 3.34 ± 1.62 |
FIX was incubated at increasing concentrations (0-20μM) with IgG (167nM) of 3 patients with acquired hemophilia for 24 hours at 37°C. Hydrolysis rates were computed, and the data were fitted to the Michaelis-Menten equation to derive the apparent Vmax and average Km. Data are the mean ± SE of 3 independent experiments.