Table 4.
Kinetic properties of 2-CysPrx WT and variants
Peroxidase activity of the variants that possessed CysP was analysed with five different concentrations of EcTrx and 75 μM hydrogen peroxide. The data were analysed using the Dalziel equation. Additionally, the apparent peroxidase activity of 5 μM 2-CysPrx and variants was analysed using 1mM DTT as reductant and 100 μM hydrogen peroxide. All data are means±SD (n=3). ND, not determined.
| 2-CysPrx | k 1 (H2O2) (104 M-1 s–1) | k 2 (Trx) (104 M-1 s–1) | V max (s–1) | K M (H2O2), µM-1 | K M (Trx) (µM) | DTT (V max app, min–1) |
|---|---|---|---|---|---|---|
| WT | 3.23±0.02 | 2.24±0.63 | 0.38±0.13 | 12±4 | 17±1 | 0.31±0.10 |
| His6 variant | 6.35±1,66 | 2.26±0.29 | > | – | – | 1.20±0.07 |
| ΔC | 2.64±0,17 | 2.16±1.15 | > | – | – | ND |
| T92D | 2.7±0.6 | 2.0±0.7 | 0.52±0.25 | 83±26 | 105±24 | ND |
| F84R | 8.3±1.0 | 1.14±0.21 | 0.70±0.42 | 8.8±6.1 | 59±26 | 0.36±0.04 |
| C176S | ND | ND | ND | ND | ND | 0.24±0.10 |