Table 2.
Kinetic parameters of Op MAL1 and MAL1 mutant Thr200Val
| Substrate | MAL1 | MAL1 Thr200Val | ||||
|---|---|---|---|---|---|---|
| K m (mm) ± SD | k cat (1/min) ± SD | k cat/Km (1/mm/min) ± SD | K m (mm) ± SD | k cat (1/min) ± SD | k cat/Km (1/mm/min) ± SD | |
| Maltose‐like substrates | ||||||
| α‐pNPGb | 0.52 ± 0.05 | 8476.4 ± 297.8 | 16300.7 | 0.37 ± 0.03 | 4870.0 ± 255.0 | 13262.4 |
| Maltose | 51.8 ± 3.7 | 10395.3 ± 297.8 | 200.7 | 375.9 ± 26.1 | 2104.1 ± 64.3 | 5.6 |
| Sucrose | 25.1 ± 2.4 | 10984.2 ± 416.9 | 437.6 | 104.8 ± 10.1 | 5121.4 ± 709.1 | 48.9 |
| Turanose | 34.0 ± 2.6 | 11864.3 ± 370.5 | 348.9 | 157.3 ± 14.6 | 5713.6 ± 281.7 | 36.3 |
| Maltotriose | 20.2 ± 1.7 | 13597.9 ± 377.2 | 673.2 | 137.9 ± 8.8 | 4434.6 ± 150.1 | 32.2 |
| Maltulose | 15.8 ± 0.8 | 2038.0 ± 33.1 | 129.0 | 7.3 ± 0.7 | 596.1 ± 28.4 | 81.4 |
| Melezitose | 115.0 ± 8.2 | 3870.9 ± 145.6 | 33.7 | 10 000a | NA | NA |
| Isomaltose‐like substrates | ||||||
| α‐MG | 35.5 ± 3.3 | 1806.4 ± 66.2 | 50.9 | 49.3 ± 4.1 | 2342.4 ± 108.4 | 47.5 |
| Isomaltose | 27.3 ± 2.3 | 1191.1 ± 72.9 | 43.6 | 40.8 ± 4.0 | 2100.8 ± 103.9 | 51.5 |
| Palatinose | 6.8 ± 0.4 | 1495.4 ± 26.5 | 219.9 | 11.4 ± 0.47 | 2276.2 ± 29.1 | 200.0 |
a
The value of K m was too high to be measured accurately and was set to. 10 000.
b
Specific activities were quantified according to release of pNP.
NA, not applicable; SD, standard deviation of the mean value.