Table 2. Effect of metal ions on the activity of dihydropyrimidinase.
| Metal ions added | Specific activity | Fold |
|---|---|---|
| (1 mM) | (μmol/mg/min) | |
| None | 0.82 ± 0.06 | 1.0 |
| CoCl2 | 5.80 ± 0.16 | 7.1 |
| ZnCl2 | 2.90 ± 0.10 | 3.5 |
| MnCl2 | 1.72 ± 0.09 | 2.1 |
| CdCl2 | 0.74 ± 0.04 | 0.9 |
| NiCl2 | 0.91 ± 0.06 | 1.1 |
| MgCl2 | 0.82 ± 0.05 | 1.0 |
| CaCl2 | 0.82 ± 0.05 | 1.0 |
The activity of purified dihydropyrimidinase (without any metal supplement in the culture) toward dihydrouracil was analyzed by the standard assay. Metal ions were added to the reaction mixture for dihydropyrimidinase activation.