Table 1.
Enzyme kinetic parameters for the sugar transfer of OsUGT91C1 and the mutants.
| Substrate | Enzyme | kcat (min−1) | Km (μM) | kcat/Km (s−1 M−1) | Fold |
|---|---|---|---|---|---|
| Rubu | WT | 2.0 ± 0.1 | 49.5 ± 5.3 | 673 | 1 |
| (Combined β (1–2) | F208M | 2.4 ± 0.1 | 20.9 ± 1.7 | 1914 | 2.8 |
| at R1 and R2) | H93W | 1.3 ± 0.1 | 56.8 ± 8.5 | 381 | 0.6 |
| F379A | 2.7 ± 0.1 | 16.5 ± 2.8 | 2727 | 4.1 | |
| H93W/F208M | 1.8 ± 0.1 | 43.6 ± 5.4 | 688 | 1.0 | |
| F379A/F208M | 2.8 ± 0.1 | 11.7 ± 1.0 | 3989 | 5.9 | |
| S13G | WT | 2.9 ± 0.1 | 24.9 ± 2.5 | 1941 | 1 |
| (β (1–2) at R1) | F208M | 3.9 ± 0.1 | 18.7 ± 1.7 | 3476 | 1.8 |
| H93W | 3.9 ± 0.1 | 36.2 ± 4.7 | 1796 | 0.9 | |
| F379A | 5.8 ± 0.2 | 19.0 ± 2.6 | 5088 | 2.6 | |
| H93W/F208M | 3.5 ± 0.1 | 29.1 ± 2.2 | 2005 | 1.0 | |
| F379A/F208M | 3.5 ± 0.1 | 9.7 ± 1.9 | 6014 | 3.1 | |
| Reb A | WT | 1.22 ± 0.02 | 45.7 ± 3.0 | 445 | 1 |
| (β (1–2) at R2) | F208M | 2.9 ± 0.1 | 25.2 ± 2.0 | 1918 | 4.3 |
| H93W | 0.60 ± 0.03 | 58 ± 12 | 172 | 0.4 | |
| F379A | 1.16 ± 0.02 | 37.0 ± 2.5 | 523 | 1.2 | |
| H93W/F208M | 2.05 ± 0.03 | 63.9 ± 3.6 | 535 | 1.2 | |
| F379A/F208M | 1.7 ± 0.1 | 15.1 ± 2.6 | 1876 | 4.2 | |
| STB | WT | 0.63 ± 0.03 | 71 ± 12 | 148 | – |
| (β (1–6) at R1) | H93W | ND | – | – | – |
| F379A | ND | – | – | – | |
| H93W/F208M | ND | – | – | – | |
| F379A/F208M | ND | – | – | – |
WT wild type, ND non-detectable, fold fold change over the kcat/Km of the wide type for each substrate.
Assays were performed as described in Methods section. Nonlinear fitting values ±SD (n = 3) are shown. Source data are provided as a Source Data file.