FIX specific activity and FVIII bypassing activity of hFIX variants derived from hFIX Y259F/K265T/Y345T
| FIX variant . | FIX act. (%) ± SEM . | FVIII byp. act. (%) ± SEM . |
|---|---|---|
| hFIX Y259F/K265T/Y345T | 73.2 ± 6.3 | 2.0 ± 0.2 |
| hFIX Y259F | 96.9 ± 11.1 | 0 |
| hFIX K265T | 191.1 ± 14.0 | 6.6 ± 0.7 |
| hFIX Y345T | 50.9 ± 8.1 | 0 |
| hFIX Y259F/K265T | 141.0 ± 20.5 | 5.8 ± 0.9 |
| FIX variant . | FIX act. (%) ± SEM . | FVIII byp. act. (%) ± SEM . |
|---|---|---|
| hFIX Y259F/K265T/Y345T | 73.2 ± 6.3 | 2.0 ± 0.2 |
| hFIX Y259F | 96.9 ± 11.1 | 0 |
| hFIX K265T | 191.1 ± 14.0 | 6.6 ± 0.7 |
| hFIX Y345T | 50.9 ± 8.1 | 0 |
| hFIX Y259F/K265T | 141.0 ± 20.5 | 5.8 ± 0.9 |
Positions Y259, K265, and Y345 correspond to Y94, K98, and Y177 in chymo-trypsinogen numbering. Values represent activity measured by 1-stage assay in FIX-deficient plasma for FIX specific activity and in FVIII-deficient plasma for FVIII bypass activity divided by FIX antigen levels. One hundred percent representing the specific activity of 200 IU/mg measured in presence of FVIII, that is, normal plasma–derived FIX has 100% FIX specific activity and close to 0 % FVIII bypassing activity. Mean values were obtained from at least 6 independent measurements ± SEM.