Table 1. Kinetic parameters of rice GH5BG in the hydrolysis of pNP glycosides, disaccharides and oligosaccharides.
Insufficient activity was detected to enable parameters to be determined for the pNP glycoside pNP β-D-mannoside or the oligosaccharides laminaritriose, laminaritetraose, laminaripentaose, laminarin and barley (1→3),(1→4)-β-glucans.
| Substrate | kcat (s−1) | Km (mM) | kcat/Km (s−1·mM−1) |
|---|---|---|---|
| pNP glycosides | |||
| pNP β-D-glucoside | 36.1±0.7 | 0.47±0.03 | 77±4 |
| pNP β- D-fucoside | 24.5±0.5 | 0.17±0.07 | 144±3 |
| pNP β-D-galactoside | 27±3 | 1.30±0.10 | 20.7±0.5 |
| pNP β-D-xyloside | 3.2±0.3 | 0.27±0.05 | 11.9±1.5 |
| pNP α-L-arabinoside | 2.88±0.08 | 0.14±0.02 | 21±3 |
| pNP β-D-cellobioside | 2.07±0.09 | 6.23±0.17 | 0.34±0.01 |
| Disaccharides | |||
| Cellobiose | 4.3±0.8 | 16.4±1.9 | 0.27±0.02 |
| Laminaribiose | 36±5 | 7.0±1.1 | 5.05±0.07 |
| Oligosaccharides | |||
| Cellotriose | 41±5 | 4.53±0.01 | 9.1±1.2 |
| Cellotetraose | 38±2 | 4.09±0.17 | 9.3±0.9 |
| Cellopentaose | 35.5±0.4 | 3.4±0.4 | 10.4±0.4 |
| Cellohexaose | 9.7±0.8 | 2.2±0.5 | 4.5±0.5 |