Table 2.
Kinetics parameters for FXa generation by FXase with FVIII mutants
| FVIII form | Km | Vmax |
|---|---|---|
| nM | nM·min−1 | |
| Wild type | 46.6 ± 6.0 | 133 ± 5 |
| Met2010Ala | 48.0 ± 4.1 | 76.0 ± 10.0† |
| Ser2011Ala | 36.4 ± 5.1 | 109 ± 4† |
| Thr2012Ala | 72.6 ± 8.4* | 189 ± 6† |
| Leu2013Ala | 46.8 ± 3.2 | 129 ± 3 |
| Phe2014Ala | 58.5 ± 7.3 | 88.7 ± 6.8† |
| Leu2015Ala | 46.1 ± 5.1 | 120 ± 4 |
| Val2016Ala | 39.3 ± 5.4 | 151 ± 12 |
| Thr2012Ala/Phe2014Ala | 93.2 ± 16.3* | 194 ± 12† |
| Thr2012Ala/Leu2013Ala/Phe2014Ala | 168 ± 26.4† | 131 ± 15 |
|
| ||
| Reconstituted A2/A3C1C2 form | Km | Vmax |
|
| ||
| nM | nM·min−1 | |
| Wild type | 29.5 ± 2.0 | 14.1 ± 0.8 |
| Thr2012Ala | 62.6 ± 5.7† | 12.7 ± 0.3 |
| Phe2014Ala | 63.7 ± 6.2† | 7.6 ± 0.4 |
| Thr2012Ala/Phe2014Ala | 78.4 ± 4.5† | 12.9 ± 2.0 |
| Thr2012Ala/Leu2013Ala/Phe2014Ala | 124 ± 21† | 9.8 ± 1.5 |
Reactions were performed as described under Materials and Methods. Km and Vmax values ± standard deviations were calculated by Michaelis-Menten kinetics.
*
P < 0.05 or
†
P < 0.01 compared with the value for wild type.