TABLE 2.
Purification of NphA1 and His-NphA2
| Step | Vol (ml) | Amt of protein (mg ml−1) | Total activity (mU)a | Sp act (mU mg−1)a,b | Yield (%) |
|---|---|---|---|---|---|
| NphA1 | |||||
| Cell extract | 20 | 4.68 | 1,048 | 11.2 ± 1.9 | 100.0 |
| HiTrap Q-Sepharose | 12 | 2.39 | 703 | 24.5 ± 3.1 | 67.1 |
| His-NphA2 | |||||
| Cell extract | 12 | 6.32 | 20,700 | 248 ± 49 | 100.0 |
| Ni-NTA | 10 | 0.24 | 8,150 | 3460 ± 820 | 39.4 |
a
One unit of 4-NP-oxidizing activity of NphA1 was defined as the amount required to convert 1 μmol of 4-NP into 4-NC per min, while 1 U of NADH-oxidizing activity of His-NphA2 was defined as the amount required to oxidize 1 μmol of NADH per min.
b
The specific activities shown here were determined from at least three independent experiments.