TABLE 1.
Reductase and oxidase activities of RdxA and RdxB and respective GST fusions for various substrates
| Activity type | Substrate (acceptor) | Sp act (μmol/min/mg of protein) ± SEa |
||||
|---|---|---|---|---|---|---|
| GST-RdxA | RdxAb | GST-RdxB | RdxBb | GST | ||
| Oxidase | NADPH (O2) | 2.4 ± 0.50 | 2.1 ± 0.01 | 0.3 ± 0.04 | 1.25 ± 0.01 | <0.01 |
| Reductase | Mtz, anaerobic | 0.18 ± 0.07 | 0.19 ± 0.02 | 0.03 ± 0.01 | 0.06 ± 0.01 | <0.01 |
a
Specific activities were calculated as the means of results from two assays from two independent purifications of the protein ± standard errors.
b
GST-RdxA or GST-RdxB was treated with thrombin to cleave the fusion proteins and release the free nitroreductase protein. Thrombin was removed from the nitroreductases by benzamidine Sepharose 6B.