Specific activities of recombinant factor XIa in chromogenic substrate assays and factor IX activation assays
| . | S-2366 . | Factor IX . | |||
|---|---|---|---|---|---|
| Km, μM . | kcat, sec−1 . | Km, μM . | kcat, min−1 . | kcat/Km . | |
| Wild-type | 400 | 200 | 0.28 | 10 | 35.7 |
| Factor XI-R226 | 350 | 160 | 1.47 | 53.2 | 36.2 |
| Factor XI-N248 | 450 | 180 | 0.36 | 8.1 | 22.5 |
| . | S-2366 . | Factor IX . | |||
|---|---|---|---|---|---|
| Km, μM . | kcat, sec−1 . | Km, μM . | kcat, min−1 . | kcat/Km . | |
| Wild-type | 400 | 200 | 0.28 | 10 | 35.7 |
| Factor XI-R226 | 350 | 160 | 1.47 | 53.2 | 36.2 |
| Factor XI-N248 | 450 | 180 | 0.36 | 8.1 | 22.5 |
Kinetic parameters for the cleavage of chromogenic substrate S-2366 and the activation of purified factor IX were determined for the activated forms of recombinant wild-type factor XI, factor XI-R226, and factor XI-N248. The assays were conducted as described in “Materials and methods,” and all results are means of duplicate experiments.