Table IV. Specific activity of site-directed mutants of TgTCEA1.
Enzyme activity was measured using 4 mm 6-tuliposide A as substrate. Data are expressed as means ± sd (n = 3).
| Mutant | Specific Activitya | Relative Activity |
|---|---|---|
| units mg−1 protein | % | |
| TgTCEA1 | 326 ± 26.3 | 100 |
| G152A | 0.355 ± 0.0280 | 0.1 |
| G153A | 0.0417 ± 0.00458 | 0.01 |
| G154A | 287 ± 7.78 | 88 |
| S235A | 0.0322 ± 0.00467 | 0.01 |
| D327N | 0.396 ± 0.0231 | 0.1 |
| H359A | 0.00263 ± 0.000215 | 0.0008 |
| H362A | 19.8 ± 0.411 | 6 |
a
One unit of enzyme activity is defined as the amount of enzyme that catalyzes 6-tuliposide A conversion to tulipalin A at a rate of 1 μmol min−1.