Table 3.
Kinetic properties of wild-type nitrate reductase and four variants
| Enzyme | Fd KM (μM) | NO3- KM (μM) | Relative MV-linked specific activitya | Relative Fd-linked specific activityb |
|---|---|---|---|---|
| Wild-Type | 38.0±3.7 | 6.0±1.0 | 100 | 100 |
| K58Q | nd | Nd | <0.1 | <0.1 |
| K58R | nd | Nd | <0.1 | <0.1 |
| R70Q | nd | nd | <0.1 | <0.1 |
| R70K | nd | nd | <0.1 | <0.1 |
| K130Q | 106±17 | 3.3±0.5 | 26 | 22 |
| K130R | 40.0±8.0 | 5.7±2.5 | 55 | 65 |
| R146Q | 51.0±5.0 | 2.5±0.3 | 91 | 87 |
a
100% = 860 μmol of nitrite produced/min/mg enzyme
b
100%= 35.0±2.2 μmol of nitrite produced/min/mg enzyme
nd = Not determined