TABLE 4.
Carbon catabolite repression of histidase expression in wild-type, tnrA, and ΔglnA strains
| Relevant genotypea | Value for cells grown onb:
|
|||
|---|---|---|---|---|
| Glucose
|
Citrate
|
|||
| Doubling time (min) | Histidase sp act (U/mg of protein) | Doubling time (min) | Histidase sp act (U/mg of protein) | |
| Wild type | 70 | 3.3 | 102 | 180 |
| tnrA | 75 | 3.4 | 100 | 256 |
| ΔglnA | 101 | 54.5 | NGc | |
| tnrA ΔglnA | 74 | 3.1 | 107 | 184 |
a
All strains were derivatives of strain 168.
b
Histidase levels are the averages of two or more determinations, which did not vary by more than 25%. Cultures were grown in MOPS minimal medium containing glutamine as the nitrogen source and the indicated carbon source. Histidine was added to induce hut expression.
c
NG, no growth. The ΔglnA strain grows only for several generations before entering stationary phase in this medium.