TABLE 2.
Kinetic constants determined for ADP and ATP hydrolysis of TgNTPDase1ΔCC and TgNTPDase3ΔCC in magnesium or calcium buffer using the ITC-based enzyme assay
| kcat | Km | kcat/Km | Ratio (kcat/Km) ATP/(kcat/Km)ADP | |
|---|---|---|---|---|
| s−1 | mm | s−1/mm | ||
| TgNTPDase1ΔCC | ||||
| ADP/Mg2+ | 238 ± 14 | 1.17 ± 0.05 | 204 ± 15 | 0.40 |
| ATP/Mg2+ | 276 ± 27 | 3.4 ± 0.5 | 81 ± 15 | |
| ADP/Ca2+ | 333 ± 15 | 1.30 ± 0.16 | 255 ± 34 | 0.57 |
| ATP/Ca2+ | 349 ± 22 | 2.4 ± 0.2 | 150 ± 20 | |
| TgNTPDase3ΔCC | ||||
| ADP/Mg2+ | 18 ± 1 | 1.25 ± 0.15 | 15 ± 2 | 202 |
| ATP/Mg2+ | 2290 ± 74 | 0.8 ± 0.2 | 3000 ± 800 | |
| ADP/Ca2+ | 13.2 ± 0.3 | 2.3 ± 0.2 | 5.8 ± 0.6 | 177 |
| ATP/Ca2+ | 588 ± 52 | 0.572 ± 0.009 | 1030 ± 90 | |