Table 1. IC50 values for compounds tested against BmDHFR and WbDHFR.
| IC50 (μM) | KI (μM) | |||
|---|---|---|---|---|
| Compounds | BmDHFR | WbDHFR | BmDHFR | WbDHFR |
| Methotrexate | 0.0022 ± 0.0014 | 0.018 ± 0.003 | <0.0005 ± 0.0003 | 0.0007 ± 0.0001 |
| Trimethoprim | 65 ± 13 | 83 ± 25 | 15 ± 3 | 5.98 ± 0.06 |
| Raltitrexed | 7.3 ± 0.2 | 18 ± 10 | 1.6 ± 0.04 | 2 ± 1 |
| Pyrimethamine | 16 ± 7 | 454 ± 37 | 3.6 ± 1.5 | 15 ± 6 |
| Aminopterin | 0.0075 ± 0.0003 | 0.014 ± 0.005 | <0.0017 ± 0.0001 | 0.0021 ± 0.0005 |
| (-)-Epicatechin gallate | >1000 | >1000 | NA | NA |
| (-)-Epicatechin | >2500 | >2500 | NA | NA |
| Vitexin | >240 | >240 | NA | NA |
The values are averages from triplicates with standard deviations shown. The experiments for each compound and enzyme were conducted at pH 6.0, at room temperature, with 100 μM NADPH, 50 μM DHF, and 40 nM BmDHFR or 12.1 nM WbDHFR in a side-by-side format, using the same solutions. The IC50 values were obtained using the Hill Equation in KaleidaGraph. The KI values for WbDHFR were obtained from Dixon plots (Fig 5 and S3 Fig) by evaluating the initial velocity against varying concentrations of inhibitor and DHF. The KI values for BmDHFR were obtained using the Cheng-Prusoff Equation.