Table 5.
Kinetic Parameters of Vv GT6-Q373H, Vv GT6-P19T, and Vv GT5-R140W-T19P as Analyzed with Quercetin as a Sugar Acceptor
| Substrate | kcat (s−1) | Km (μM) | kcat/Km (s−1 μM−1) |
| Vv GT6-Q373H (GlcT activity) | |||
| Quercetina | 0.026 ± 0.002 | 22.6 ± 14.9 | 0.0012 |
| UDP-Glcb | 157 ± 34 | 0.00017 | |
| Vv GT6-Q373H (GalT activity) | |||
| Quercetina | 5.89 ± 0.74 | 25.1 ± 11.9 | 0.23 |
| UDP-Galb | 439 ± 55 | 0.0134 | |
| Vv GT6-P19T (GlcT activity) | |||
| Quercetina | 0.24 ± 0.02 | 34.9 ± 7.9 | 0.0069 |
| UDP-Glcb | 62.3 ± 9.5 | 0.0038 | |
| Vv GT6-P19T (GalT activity) | |||
| Quercetina | 0.19 ± 0.02 | 21.5 ± 7.3 | 0.0088 |
| UDP-Galb | 118 ± 7.3 | 0.0016 | |
| Vv GT5-R140W-T19P (GlcT activity) | |||
| Quercetina | 1.40 ± 0.03 | 120 ± 59 | 0.012 |
| UDP-Glcb | 251 ± 58 | 0.0056 | |
| Vv GT5-R140W-T19P (GalT activity) | |||
| Quercetina | 0.66 ± 0.06 | 47.3 ± 12 | 0.014 |
| UDP-Galb | 337 ± 21 | 0.0019 | |
a
Kinetic parameters were determined at pH 7.4 with the appropriate UDP-sugar (1.0 mM), as described in Methods.
b
100 μM quercetin was used as the sugar acceptor.