Table 2.
Kinetic parameters of recombinant BmSUH and its mutants for sucrose and maltotriose compared with GH13_17 α-glucosidases
| Enzyme | Sucrose |
Maltotriose |
Reference | ||||||
|---|---|---|---|---|---|---|---|---|---|
| kcat | Km | kcat/Km | Relative kcat/Kma | kcat | Km | kcat/Km | Relative kcat/Km | ||
| s−1 | mm | s−1 mm−1 | -fold | s−1 | mm | s−1 mm−1 | -fold | ||
| BmSUH | This study | ||||||||
| WT | 41.2 ± 0.6 | 0.92 ± 0.06 | 44.7 | 1 | 0.29 ± 0.01 | 6.73 ± 0.66 | 0.043 | 1 | |
| Q191V | 26.0 ± 0.7 | 1.36 ± 0.14 | 19.1 | 0.43 | 0.51 ± 0.01 | 3.09 ± 0.21 | 0.165 | 3.8 | |
| D247N (nucleophile) | NDb | ND | ND | ND | |||||
| Y251H | 40.4 ± 0.9 | 1.95 ± 0.17 | 20.7 | 0.46 | 2.09 ± 0.06 | 1.63 ± 0.39 | 1.28 | 30 | |
| E322Q (acid/base) | ND | ND | ND | ND | |||||
| E440A | 14.9 ± 0.5 | 0.89 ± 0.14 | 16.7 | 0.37 | 1.30 ± 0.02 | 1.56 ± 0.16 | 0.833 | 19 | |
| HBG-II | 87.6 | 30.6 | 2.91 | 87.2 | 3.82 | 22.8 | 33 | ||
| HBG-III | 222 | 42.3 | 5.27 | 133 | 8.56 | 15.6 | 33 | ||
| Cqm1 | 329 | 7.74 | 44.6 | 320 | 2.18 | 147 | 34 | ||
a Normalized to the kcat/Km value of WT BmSUH toward each substrate.
b ND, not detected.