TABLE 2.
Enzyme activities of select mutants with alterations in the pyruvate node
| Strain | Relevant genotype | Enzymes presenta | Enzyme activity (μmol min−1 mg of protein−1)b |
||
|---|---|---|---|---|---|
| LDH | PDH | ADH | |||
| PMD23 | Wild type | PFL, LDH | 1.52 | 0.46 | 0.04 |
| QZ2 | lpd101 | PFL, LDH, PDH* | 0.41 | 0.14 | 0.05 |
| QZ3 | lpd101 ldhA | PFL, PDH* | 0.01 | 0.44 | 0.04 |
| YK167 | lpd101 pflB | LDH, PDH* | 4.17 | 0.32 | 0.06 |
a
PFL, pyruvate formate-lyase; LDH, fermentative lactate dehydrogenase; PDH*, pyruvate dehydrogenase complex with a mutation in dihydrolipoamide dehydrogenase.
b
Determined in extracts of cells harvested from fermenter cultures in the mid-exponential phase of growth. ADH, alcohol dehydrogenase. See Materials and Methods for assay conditions and other details.