TABLE 2.
Thiosulfate reductase activity by cell extracts of E. coli DH5α strains harboring phsABC constructs
| Plasmid | Aerobic culture
|
Anaerobic culture
|
||
|---|---|---|---|---|
| Enzyme activitya (U/g [dry wt]) | Relative activityb | Enzyme activity (U/g [dry wt]) | Relative activity | |
| Controld | 138 ± 26 | 1 | 218 ± 22 | 1.6 |
| pSB74 | 324 ± 49 | 2.3 | 684 ± 40 | 5.0 |
| pSB77 | 209 ± 31 | 1.5 | 627 ± 27 | 4.5 |
| pSB103 | 191 ± 27 | 1.4 | 529 ± 27 | 3.8 |
| pSB107 | 187 ± 22 | 1.4 | 498 ± 31 | 3.6 |
a
One unit is equivalent to 1 μmol of sulfite produced/min in a 1.0-ml assay system. Mean values from three replicate experiments are reported.
b
The relative activity is the ratio of the thiosulfate reductase activity in the cell extracts from E. coli strains harboring phsABC constructs grown aerobically or anaerobically to that in the control cells grown aerobically.