Table 2.
Effects of various compounds and metal ions on the activity of Sb-PDE from Sphingobium sp. TCM1.
| Compound | Concentration (mM) | Relative activity (%) |
|---|---|---|
| None | — | 100 |
| MgCl2 | 0.1 | 100 |
| CaCl2 | 0.1 | 105 |
| MnCl2 | 0.1 | 131 |
| FeCl2 | 0.1 | 96 |
| CoCl2 | 0.1 | 95 |
| NiCl2 | 0.1 | 101 |
| CuCl2 | 0.1 | 87 |
| ZnCl2 | 0.1 | 128 |
| EDTA | 1 | 95 |
| 10 | 110 | |
| EGTA | 1 | 98 |
| 10 | 105 | |
| o-Phenanthroline | 1 | 2 |
| Dithiothreitol | 1 | 4 |
| 2-Mercaptoethanol | 1 | 46 |
| N-Ethylmaleimide | 1 | 98 |
| p-Chloromercuribenzoic acid | 1 | 107 |
The activity of Sb-PDE was measured using the standard assay mixture with BpNpp as the substrate. The final enzyme concentration was 1.9 µg/ml. The activity without addition of metal ions or compounds was defined as 100%.