TABLE 2.
Effect of prp mutations on the expression of the prpBCDE operon
| Strain | Relevant genotypea | Mean β-galactosidase activity ± SD (U/A650 unit)b | % Expressionc |
|---|---|---|---|
| JE4043 | prpRBCDE+/pRS551 (vector control) | 27 ± 17 | NA |
| JE4044 | prpRBCDE+/pPRP25 (PprpBCDE-lacZ+) | 20,696 ± 850 | 100 |
| JE4390 | prpC173/pPRP25 (PprpBCDE-lacZ+) | 1,320 ± 130 | 6 |
| JE4391 | prpC167/pPRP25 (PprpBCDE-lacZ+) | 974 ± 160 | 5 |
| JE4393 | prpD169/pPRP25 (PprpBCDE-lacZ+) | 6,987 ± 687 | 34 |
| JE4392 | prpD174/pPRP25 (PprpBCDE-lacZ+) | 7,568 ± 655 | 36 |
| JE4394 | prpE213/pPRP25 (PprpBCDE-lacZ+) | 14,039 ± 1,578 | 68 |
| JE4389 | prpB195/pPRP25 (PprpBCDE-lacZ+) | 18,767 ± 1,102 | 91 |
| JE4388 | prpB210/pPRP25 (PprpBCDE-lacZ+) | 18,267 ± 395 | 88 |
a
All strains were derivatives of strain TR6583 (metE205 ara-9).
b
Assays were performed with mid-log-phase cultures grown in NCE medium supplemented with propionate, glycerol, and methionine. Assays conditions have been described elsewhere (7). A unit of activity was defined as the amount of enzyme that catalyzed the hydrolysis of 1 nmol of ONPG per min.
c
Obtained by dividing the level of expression of the lacZ gene in the mutant by the level of expression of the lacZ gene in the wild-type strain and multiplying by 100. Numbers are rounded up to the closest integer. NA, not applicable.