Table II.
WXyn43 kinetic constants in comparison with reported data on β-xylosidases from XynB2 (Michlmayr et al. 2013) and LbX (Jordan et al. 2013), both from strains of L. brevis
| β-Xylosidase | Substrate | Kinetic constant |
||
|---|---|---|---|---|
| kcat (s−1) | KM (mM) | kcat/KM (s−1 mM−1) | ||
| WXyn43 | ||||
| p-Nitrophenyl-β-d-xylopyranoside | 258 ± 11 | 7.4 ± 1.1 | 34.9 ± 5.4 | |
| (1 → 4)-β-d-Xylobiose | 961 ± 25 | 7.2 ± 0.5 | 133.5 ± 9.9 | |
| (1 → 4)-β-d-Xylotriose | 900 ± 13 | 6.5 ± 0.3 | 138.5 ± 6.7 | |
| (1 → 4)-β-d-Xylotetraose | 770 ± 7 | 17 ± 0.3 | 45.3 ± 0.9 | |
| XynB2a | ||||
| p-Nitrophenyl-β-d-xylopyranoside | 46 | 11 ± 1 | 4.1 | |
| (1 → 4)-β-d-Xylobiose | 233 | 4.8 ± 0.4 | 48 | |
| LbXb | ||||
| p-Nitrophenyl-β-d-xylopyranoside | 73.4 ± 1.5 | 6.93 ± 0.26 | 10.6 ± 0.2 | |
| (1 → 4)-β-d-Xylobiose | 407 ± 9 | 2.96 ± 0.24 | 138 ± 9 | |
| (1 → 4)-β-d-Xylotriose | 235 ± 4 | 2.91 ± 0.15 | 80.8 ± 3.0 | |
| (1 → 4)-β-d-Xylotetraose | 146 ± 4 | 2.40 ± 0.08 | 32.6 ± 1.2 | |
aReactions performed at 37°C and pH 5.5 and b25°C and pH 6.0.