Table 1.
Activity of recombinant G. lamblia nitroreductases (GlNR1 and GlNR2) with various nitro- and non-nitro compounds (0.1 mM) as substrates. Functional assays were performed with MTT as chromogenic electron acceptor. Electron donor was NADH or NADPH if specified. The reaction was performed at 37 °C and stopped after various time points by addition of one volume pure ethanol. Mean values (±SE) are given for three replicates after subtraction of enzyme and substrate blanks.
| Substrate | GlNR1 | GlNR2 |
|---|---|---|
| (ΔA590 min−1 mg prot−1) | ||
| Menadione | 22.9 ± 0.4 | 16.2 ± 0.2 |
| Menadione NADPH | 1.8 ± 0.2 | 0.2 ± 0.1 |
| Dicoumarol | 3.1 ± 0.2 | 0.8 ± 0.1 |
| Menadione + dicoumarol | 27.2 ± 0.3 | 14.5 ± 0.1 |
| Ubiquinone (coenzyme Q10) | 2.8 ± 0.1 | 1.8 ± 0.2 |
| FAD | 11.8 ± 0.4 | 8.9 ± 0.9 |
| Dinitrotoluene | 5.2 ± 0.3 | 2.8 ± 0.2 |
| Dinitrotoluene NADPH | 0.9 ± 0.3 | 0.3 ± 0.1 |
| 7-Nitrocoumarine | 10.6 ± 0.3 | 6.5 ± 0.5 |
| Dinitrophenol | 5.9 ± 0.4 | 0.2 ± 0.1 |
| Nitrophenol | 2.9 ± 0.1 | 2.6 ± 0.1 |
| Metronidazole | 2.8 ± 0.2 | 1.7 ± 0.1 |
| Nitazoxanide | 2.7 ± 0.2 | 1.9 ± 0.1 |
| CB1954 | 3.0 ± 0.1 | 1.7 ± 0.1 |
| C17 | 2.1 ± 0.2 | 0.9 ± 0.1 |