Table 1. Effects of several agents on the activity of T. cruzi IPC synthase in the absence or presence of TX-100.
Assays were performed in a final volume of 100 μl containing 100 mM Tris/maleate (pH 6.0), 1 mM PI, 100 μg of microsomal protein and 0.1 mM C6-NBD-cer at 28 °C for 30 min. All metal ions were added as the chloride salt. n.d., not determined.
| Activity [nmol·min−1·(mg of protein)−1] | ||
|---|---|---|
| Conditions | Without TX-100 | With 0.1% TX-100 |
| Without PI | 0.1482 | 0.5190 |
| PI | 2.1092 | 5.0161 |
| PI+10 mM Mg2+ | 1.7765 | 3.6726 |
| PI+10 mM Mn2+ | 0.7577 | 1.7343 |
| PI+10 mM Ca2+ | 1.4143 | 3.7845 |
| PI+10 mM Ni2+ | 0.2124 | 0.1239 |
| PI+10 mM Co2+ | 0.2320 | 0.2497 |
| PI+10 mM Cu2+ | 0.0260 | 0.0080 |
| PI+6 mg·ml−1 BSA | 0.5913 | n.d. |
| PI+10 mM CHAPS | 2.0534 | n.d. |
| PI+10 mM EGTA | 2.0671 | 8.0764 |
| PI+10 mM EDTA | 2.1856 | 9.1979 |
| PI+10 mM DTT | 2.6906 | 6.2430 |
| PI+10 mM NaF | 1.9505 | 4.8157 |