TABLE 5.
Influence of the type of hemicellulosic substrate on the activity of XynA and EngL in the free state or complexed onto mini-CbpA1&2 and mini-CbpA5&6
| Substrate | Enzyme | Free enzyme (μM) | Mini-CbpA1&2
|
Mini-CbpA5&6
|
||
|---|---|---|---|---|---|---|
| Amt (μM)a | SFb | Amt (μM)a | SFb | |||
| Corn stem | EngL | 24 (1.6) | 45 (1.7) | 1.9 | 39 (0.9) | 1.7 |
| XynA | 43 (0.9) | 87 (3.0) | 2.0 | 53 (0.9) | 1.2 | |
| Corn fiber | EngL | 15 (1.6) | 30 (1.0) | 2.0 | 31 (1.1) | 2.1 |
| XynA | 15 (0.8) | 19 (1.6) | 1.3 | 29 (2.7) | 1.9 | |
| CAX | EngL | 47 (2.9) | 100 (5.0) | 2.2 | 181 (5.4) | 3.9 |
| XynA | 55 (2.7) | 86 (1.6) | 1.6 | 79 (3.0) | 1.4 | |
| CFG | EngL | 26 (3.4) | 56 (0.1) | 2.1 | 41 (1.5) | 1.6 |
| XynA | 23 (1.5) | 55 (2.3) | 2.3 | 38 (1.0) | 1.6 | |
a
The amount of released reducing sugars from each substrate (0.5%) at 37°C for 20 h is given. The contents of the substrates are: corn stem, 40% cellulose and 20% arabinoxylan; corn fiber, 15% cellulose and 40% arabinoxylan; CAX, 21% cellulose and 68% arabinoxylan; and CFG, 2% cellulose and 85% arabinoxylan. All enzymes and mini-scaffolding proteins were in equimolar amounts at 0.25 μM. The number in parentheses indicates standard deviation.
b
SF is as described in Table 4.