TABLE 2.
Catalase activity of wild-type and mutant KatG
| KatG | kcat (s−1)a | Km (mM) | kcat/Km (M−1 s−1) | kcat/Km ratio, mutant/wild type |
|---|---|---|---|---|
| Wild type | 3,270 ± 260 | 5.9 ± 0.7 | 0.56 × 106 | 1.00 |
| A110V | 5,230 ± 210 | 10.3 ± 0.6 | 0.51 × 106 | 0.91 |
| A139P | 3,330 ± 10 | 10.7 ± 0.8 | 0.31 × 106 | 0.55 |
| S315N | 2,990 ± 70 | 16.8 ± 0.8 | 0.18 × 106 | 0.32 |
| L619P | 3,180 ± 30 | 17.1 ± 0.3 | 0.19 × 106 | 0.34 |
| L634F | 3,450 ± 380 | 14.3 ± 2.9 | 0.24 × 106 | 0.43 |
| D735A | 2,750 ± 70 | 14.8 ± 0.8 | 0.18 × 106 | 0.32 |
a
kcat is the enzyme turnover rate, a form of specific activity, and is expressed on the basis of dimeric KatG native enzyme and variants. A kcat value of 1 s−1 is equivalent to a specific activity of 0.375 μmol/mg of KatG/min.