TABLE 3.
Substrate spectrum of the PCE-RDase of Dehalobacter restrictus
| Compounda | Concn (mM) | Sp act (%)b |
|---|---|---|
| Trichloroethene | 0.5 | 100 |
| Trichlorofluoroethene | 0.4 | 62 ± 8 |
| trans-1,2-DCE | 0.4 | 0 |
| cis-1,2-DCE | 0.4 | 0 |
| 1,1-DCE | 0.4 | 0 |
| Tetrachloromethane | 0.6 | 15 ± 7c |
| Hexachloroethane | 0.4 | 60 ± 11c |
| 1,1,2,2-Tetrachloroethane | 0.4 | 21 ± 1 |
| 1,1,1,2-Tetrachloroethane | 0.4 | 17 ± 6 |
| 1,1,1-Trichloro-2,2,2-trifluoroethane | 0.5 | 14 ± 7 |
| 1,1,2-Trichloroethane | 0.5 | 43 ± 13 |
| 1,1,1-Trichloroethane | 0.5 | 1.4 ± 0.1 |
| N2O | 20 | 13 ± 5 |
No oxidation of reduced methyl viologen was observed upon addition of 2-, 3-, or 4-chlorobenzoate, 2-, 3-, or 4-chlorophenol, pentachlorophenol, nitrate, nitrite, thiosulfate, sulfite, acrylate, or fumarate at a concentration of 0.4 mM.
One unit of PCE-RDase activity corresponded to the amount of protein that catalyzed the oxidation of 2 μmol of methyl viologen radicals/μmol of Cl− formed/min at 30°C, as determined from initial rates of methyl viologen oxidation. A PCE-RDase specific activity of 250 ± 12 nkat/mg of protein was defined as 100%.
The abiotic oxidation that occurred in the presence of only reduced methyl viologen was subtracted from the significantly higher oxidation in the presence of the PCE-RDase.