Table 2.
Kinetic parameters and metal content of HPP from L. lactis.
| HPP | kcat(s−1) | Km (mM) | kcat/Km (M−1s−1) | Metal content |
|---|---|---|---|---|
| Wild-type | 174 ± 10 | 1.9 ± 0.2 | (8.9 ± 0.3) × 104 | Zn (4.5); Mn (0.8) |
| D17N | n.d.a | n.d. | (5.6 ± 0.1) × 10 | Zn (0.5) |
| H42N | 0.62 ± 0.04 | 1.3 ± 0.2 | (4.8 ± 0.6) × 102 | Zn (1.9); Fe (0.3) |
| E115Q | 31 ± 2 | 1.7 ± 0.2 | (1.8 ± 0.2) × 104 | Zn (2.2); Fe (0.4); Mn (0.4) |
| Y117F | 110 ± 3 | 0.74 ± 0.06 | (1.5 ± 0.1) × 105 | Zn (1.4) |
| Y117A | 53 ± 3 | 5.4 ± 0.6 | (9.8 ± 0.6) × 103 | Zn (1.3); Mn (0.3) |
| Y157F | 61 ± 3 | 1.7 ± 0.2 | (3.6 ± 0.3) × 104 | Zn (1.7); Fe (0.3) |
| R160M | 0.74 ± 0.04 | 1.5 ± 0.2 | (4.9 ± 0.5) × 102 | Zn (1.5) |
| R160A | n.d. | n.d. | (1.0 ± 0.1) × 102 | Zn (1.9); Fe (0.5) |
| Y161F | 180 ± 6 | 2.3 ± 0.2 | (7.9 ± 0.4) × 104 | Zn (2.3); Fe (0.3) |
| Y161A | 48 ± 1 | 2.5 ± 0.9 | (2.5 ± 0.9) × 104 | Zn (1.0); Fe (0.3) |
| R197M | 38 ± 2 | 4.5 ± 0.6 | (8.5 ± 0.7) × 103 | Zn (3.3); Fe (0.6); Mn (0.5) |
| D228N | 0.031 ± 0.002 | 0.14 ± 0.04 | (2.2 ± 0.5) × 102 | Zn (1.2) |
| H230N | n.d. | n.d. | (4.5 ± 0.1) × 102 | Zn (1.6) |
a
nd: not determined because the enzyme did not saturate at the highest substrate concentration tested.