Table 2.

Effect of prp mutations on the expression of the prpBCDE operon

StrainRelevant genotypeaMean β-galactosidase activity ± SD (U/A650unit)b% Expressionc
JE4043 prpRBCDE +/pRS551 (vector control)27 ± 17NA
JE4044 prpRBCDE +/pPRP25 (PprpBCDE -lacZ +)20,696 ± 850100
JE4390 prpC173/pPRP25 (PprpBCDE -lacZ +)1,320 ± 1306
JE4391 prpC167/pPRP25 (PprpBCDE -lacZ +)974 ± 1605
JE4393 prpD169/pPRP25 (PprpBCDE -lacZ +)6,987 ± 68734
JE4392 prpD174/pPRP25 (PprpBCDE -lacZ +)7,568 ± 65536
JE4394 prpE213/pPRP25 (PprpBCDE -lacZ +)14,039 ± 1,57868
JE4389 prpB195/pPRP25 (PprpBCDE -lacZ +)18,767 ± 1,10291
JE4388 prpB210/pPRP25 (PprpBCDE -lacZ +)18,267 ± 39588
  • 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.