TABLE 3.
Kinetic constants of the GH3 glycosidases from LbBgl and BaBgla
| Enzyme and substrate | Kinetic constant |
|||
|---|---|---|---|---|
| Km (mM) | Vmax (μmol min−1 mg−1) | kcatb (s−1) | kcat/Km (s−1 mM−1) | |
| LbBgl | ||||
| pNP-β-d-glucopyranoside | 0.63 ± 0.09 | 47 ± 1 | 66 | 104 |
| pNP-β-d-xylopyranoside | 2.6 ± 0.2 | 6.6 ± 0.2 | 9.3 | 3.5 |
| Deoxynivalenol-3-O-β-d-glucopyranoside | 2.8 ± 0.4 | 0.11 ± 0.00 | 0.15 | 0.053 |
| Cellobiose | 63 ± 4 | 5.3 ± 0.2 | 7.4 | 0.12 |
| BaBgl | ||||
| pNP-β-d-glucopyranoside | 1.1 ± 0.1 | 68 ± 2 | 94 | 87 |
| pNP-β-d-xylopyranoside | 4.2 ± 0.3 | 39 ± 1 | 53 | 13 |
| Deoxynivalenol-3-O-β-d-glucopyranoside | 5.4 ± 0.5 | 16 ± 1 | 22 | 4.0 |
| Cellobiose | 73 ± 12 | 0.50 ± 0.05 | 0.69 | 0.0094 |
a
Kinetic constants from LbBgl and BaBgl were determined at 37°C, pH 7.0 (100 mM Tris-Cl).
b
Calculations are based on the theoretical molecular mass of the His6-tagged proteins: LbBgl, 83.6 kDa; BaBgl, 82.2 kDa.