TABLE 3.
Effects of nitrate on enzyme activities of CODH, hydrogenase, and nitrate reductase in cell extracts of C. thermoaceticum
| Culture condition | Concna
|
|||||
|---|---|---|---|---|---|---|
| CODH (U/mg)
|
Hydrogenase (U/mg)
|
Nitrate reductase (mU/mg)
|
||||
| − | + | − | + | − | + | |
| 100% CO2 (stoppered) | 3.1 ± 1.0 | 2.6 ± 0.7 | 0.32 ± 0.06 | 0.24 ± 0.14 | 2.1 ± 2.1 | 13 ± 5 |
| 100% N2 (stoppered)b | 1.6 ± 0.3 | 3.7 ± 0.5 | 0.02 ± 0.002 | 0.034 ± 0.031 | 23 ± 18 | 30 ± 6 |
| 100% CO2 (sparged) | 6.9 ± 2.2 | 1.3 ± 0.5 | 0.41 ± 0.18 | 0.07 ± 0.02 | 5.1 ± 4.5 | 39 ± 4 |
| 1% CO–99% CO2 (sparged) | 10 ± 2 | 2.6 ± 0.1 | 0.39 ± 0.12 | 0.032 ± 0.026 | 0.6 ± 0.2 | 26 ± 13 |
| 1% H2–99% CO2 (sparged) | 6.5 ± 0.5 | 5.1 ± 1.3 | 0.34 ± 0.13 | 0.14 ± 0.07 | 6.3 ± 0.5 | 22 ± 9 |
| 5% H2–95% CO2 (sparged) | 7.1 ± 0.1 | 2.1 ± 0.3 | 0.50 ± 0.28 | 0.11 ± 0.03 | 12 ± 6 | 38 ± 5 |
| 0.1% NO–99.9% CO2 (sparged) | 5.0c | 1.2 ± 0.1 | 0.12c | 0.59 ± 0.35 | 20c | 30 ± 3 |
a
Mean ± standard deviation from three independent experiments for cells grown without NO3− (−) or in the presence of 30 mM NO3− (+).
b
Cells grown without NaHCO3.
c
Single experiment.