Table 2.
Kinetic constants for the hydrolysis of phosphorylated compounds by the phytate-degrading enzyme from Aspergillus niger at pH 5.0
| substrate | Km (μM) | kcat (sec-1) | kcat/KM (s-1 M-1) |
|---|---|---|---|
| phytate | 54 ± 1.4 | 190 ± 4.3 | 3518519 |
| p-nitrophenyl phosphate | 124 ± 3.9 | 35 ± 0.9 | 282258 |
| 1 -naphthyl phosphate | 247 ± 6.7 | 23 ± 1.5 | 93117 |
| 2-naphthyl phosphate | 276 ± 7.1 | 22 ± 1.3 | 79710 |
| 2-glycero phosphate | 521 ± 9.1 | 9 ± 0.3 | 17274 |
| AMP | 497 ± 8.2 | 11 ± 1.1 | 22133 |
| ADP | 534 ± 7.9 | 12 ± 0.9 | 22472 |
| ATP | 587 ± 6.5 | 8 ± 0.6 | 13629 |
| Glucose-1 -phosphate | 741 ± 6.4 | 6 ± 0.4 | 8097 |
| Phenyl phosphate | 177 ± 1.3 | 36 ± 1.7 | 203390 |
Temperature: 37°C; buffer: 100 mM sodium acetate, pH 5.0; enzyme concentration: 25 mU ml-1. The data are mean values of five independent experiments.