TABLE 4.
Effect of protease inhibitors and divalent cations on ZmpB activity
| Addition to reaction mixture | Activity (units)a | % of control activity |
|---|---|---|
| None | 5.0 ± 0.1 | 100 |
| EDTA | ||
| 1 mM | 0.2 ± 0.04* | 4.0 |
| 5 mM | 0.4 ± 0.02* | 8.0 |
| 10 mM | 0.4 ± 0.03* | 8.0 |
| 1,10-Phenanthroline | ||
| 1 mM | 0.8 ± 0.1* | 16.0 |
| 5 mM | 0.8 ± 0.1* | 16.0 |
| 10 mM | 0.8 ± 0.04* | 16.0 |
| 1,7-Phenanthroline, 10 mM | 5.4 ± 0.09 | 108 |
| Phenylmethylsulfonyl fluoride | ||
| 0.1 mM | 5.4 ± 0.22 | 108 |
| 0.5 mM | 4.9 ± 0.16 | 98 |
| 1.0 mM | 4.4 ± 0.11 | 88 |
| Phosphoramidon | ||
| 1 μM | 5.9 ± 0.06 | 118 |
| 5 μM | 6.0 ± 0.15 | 120 |
| 10 μM | 6.1 ± 0.17 | 122 |
| CaCl2, 1 mM | 4.7 ± 0.24 | 94 |
| ZnCl2, 1 mM | 0 ± 0.02* | 0 |
| ZnSO4, 1 mM | 0 ± 0.02* | 0 |
| CoCl2, 1 mM | 1.2 ± 0.03* | 24 |
| MgCl2, 1 mM | 3.6 ± 0.01 | 72 |
| MgSO4, 1 mM | 4.1 ± 0.08 | 82 |
| MnCl2, 1 mM | 2.5 ± 0.05* | 50 |
| MnSO4, 1 mM | 3.4 ± 0.07 | 68 |
| NiSO4, 1 mM | 0.3 ± 0.02* | 60 |
a
Proteolytic activity was determined using hide powder azure as the substrate. Values are means ± standard deviations *, significantly different from the control value (P < 0.01 by analysis of variance and Dunnett multiple-comparisons test).