TABLE 3.
Metabolic flux distributions of different mutant strains of E. coli affected at the pyruvate nodea
| Strain (relevant genotype) | Metabolic flux (mmol h−1 [g of cells {dry wt}]−1) for the following reactionb: |
Dry wt of cells (g/liter) | YATP (g of cells [mol of ATP]−1) | |||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| J1 (G-6-P) | J3 (G-3-P) | J4 (PEP) | J5 (PYR) | J6 (SUCC) | J7c (lactate) | J8 (formate) | J9 (PDH) | J10 (acetate) | J11 (ethanol) | J12 (pyruvate) | J13c (lactate) | NADH formation | NADH consumption | |||
| PMD23 (hypF) | 5.85 | 4.87 | 9.74 | 3.58 | 0.30 | 2.82 | 6.60 | 0.02 | 3.58 | 3.04 | 0.00 | 0.00 | 9.76 | 9.50 | 1.84 | 10.9 |
| QZ2 (lpd101 ΔhypF) | 5.00 | 4.70 | 9.40 | 4.10 | 0.30 | 2.93 | 6.00 | 0.16 | 3.37 | 2.79 | 0.01 | 0.00 | 9.56 | 9.11 | 2.18 | 12.9 |
| QZ3 (ΔldhA lpd101 ΔhypF) | 4.45 | 4.29 | 8.44 | 3.79 | 0.20 | 0.00 | 3.81 | 3.91 | 1.93 | 5.78 | 0.52 | 0.15 | 12.34 | 12.12 | 1.93 | 13.6 |
| YK167 [lpd101 Δ(focA-pflB)] | 7.30 | 7.26 | 14.53 | 6.31 | 0.91 | 8.88 | 0.00 | 4.30 | 1.01 | 3.30 | 0.43 | 0.00 | 18.83 | 17.30 | 1.50 | 6.9 |
| SE2382 [lpd101 ΔldhA Δ(focA-pflB)] | 3.62 | 3.38 | 6.20 | 2.20 | 0.38 | 0.00 | 0.00 | 4.23 | 0.92 | 3.31 | 1.59 | 0.56 | 10.44 | 7.94 | 0.69 | 7.4 |
| YK1 [lpd101 ΔldhA Δ(focA-pflB) pdhR] | 4.06 | 3.86 | 7.72 | 3.33 | 0.33 | 0.00 | 0.00 | 7.39 | 1.13 | 6.26 | 0.01 | 0.00 | 15.11 | 13.19 | 0.60 | 4.9 |
All cultures were grown anaerobically in a chemostat with glucose limitation at a dilution rate of 0.1 h−1 as described in Materials and Methods. Reactions J1, J6, J7, J8, J10, J11, J12 and J13 were measured directly, while the other reaction rates were computed.
Products of reactions are given in parentheses. G-6-P, glucose-6-phosphate; G-3-P, glyceraldehyde 3-phosphate; PEP, phosphoenolpyruvate; PYR, pyruvate; SUCC, succinate.
The lactate produced by the ldhA deletion mutants (strains QZ3 and SE2382) is assumed to be derived from the methylglyoxal (J13) pathway; in strains with LDH activity, the amount of lactate produced by the methylglyoxal pathway (J13) was considered to be negligible.