TABLE 2.
Formate hydrogenlyase activities of E. coli cultures grown in a pH-stata
| Strain | Relevant genotype | Growth medium | FHL activity (nmol · min−1 · mg of cell protein−1)
|
|
|---|---|---|---|---|
| pH 7.5 | pH 6.5 | |||
| WS222b | Wild type | LB + Glu (0.3%) | 15 | 48 |
| AH266 | Δ(hyfA to hyfJ) | 23 | 56 | |
| AH267 | Δ(hyfR) | 15 | 24 | |
| WS222 | Wild type | LB + Glu (0.1%) + formate (15 mM) | 40 | 148 |
| AH266 | Δ(hyfA to hyfJ) | 50 | 129 | |
| WS232 | Δ(hyfB to hyfG) | 66 | 136 | |
| AH267 | Δ(hyfR) | 83 | 103 | |
a
Cultures, in the indicated media, were grown anaerobically under argon gas phase at the indicated pH in a pH-stat. pH was maintained by the addition of 2 N KOH. FHL activity was determined as formate-dependent dihydrogen production by using a gas chromatograph. β-Galactosidase activities of all these cultures were below the detection limit of 50 nmol·min−1·(mg of cell protein)−1.
b
Strain WS222 carries Φ(hyfA-lacZ) via λWS4.