Table 4.
Activities of dinitrogenase complemented with NifH or apoNifH
| Form of NifH* | Pretreatment† | Concentration of dinitrogenase, μg of protein | Activity‡ |
|---|---|---|---|
| NifH | None | 0.0 | <0.01 |
| NifH | None | 50.0 | 50.3 |
| NifH | None | 5.0 | 6.3 |
| ApoNifH | None | 50.0 | <0.01 |
| 5.0 | <0.01 | ||
| ApoNifH | Plus extract of | 50.0 | <0.01 |
| strain CA11.1 | 5.0 | <0.01 | |
| ApoNifH | Plus extract of | 50.0 | <0.01 |
| strain DJ54 | 5.0 | <0.01 |
*
Assays contained purified NifH or apoNifH (0.1 mg of protein) with high (50.0 μg of protein) or low (5.0 μg of protein) concentrations of purified dinitrogenase.
†
ApoNifH (0.1 mg of protein) was preincubated with 0.2 ml of extracts of either DJ54 or CA11.1 for 30 min at 30°C, after which the appropriate concentration of purified dinitrogenase was added.
‡
Expressed as nmol C2H4 formed per minute.