Table 2. Comparison of paAzoR1 and Y131F.
Apparent values of the Michaelis–Menten constants (K m), maximum velocities (V max) and turnover numbers (k cat) of purified recombinant paAzoR1 with different substrates are reported. The term apparent indicates that the kinetic constants were determined by varying the concentration of one substrate while keeping the concentration of the other constant. The values for methyl red and balsalazide were determined with NADPH (at 500 µM) as the electron donor and the values for NADH and NADPH were determined with methyl red at 50 µM as the azo substrate (Wang et al., 2007 ▶).
| Apparent kinetic constants | MRE | Balsalazide | NADH | NADPH | |
|---|---|---|---|---|---|
| PaAzoR1 | Vmax (µM s−1) | 0.28 ± 0.01 | 0.81 ± 0.02 | 0.22 ± 0.01 | 0.74 ± 0.03 |
| Km (µM) | 92.7 ± 7.6 | 98.6 ± 4.2 | 538 ± 21 | 1197 ± 33 | |
| kcat (s−1) | 12.7 ± 0.5 | 36.8 ± 1.1 | 10.0 ± 0.5 | 33.6 ± 2.0 | |
| Y131F | Vmax (µM s−1) | 0.42 ± 0.02 | 0.53 ± 0.02 | 0.55 ± 0.02 | 0.78 ± 0.04 |
| Km (µM) | 44.5 ± 2.2 | 102.9 ± 3.2 | 965 ± 25 | 535 ± 25 | |
| kcat (s−1) | 19.1 ± 0.9 | 24.1 ± 0.3 | 25.2 ± 0.9 | 35.5 ± 1.0 |