Table 5.
Metabolic flux ratio (METAFoR) analysis results
| % Fraction of total pool | Expressing Strain | Control Strain | ||||
|---|---|---|---|---|---|---|
| 21% O2 | 11% O2 | 8% O2 | 21% O2 | 11% O2 | 8% O2 | |
| Pep from PPs, upper bound | 50 ± 9 | 23 ± 6 | 15 ± 7 | 39 ± 9 | 32 ± 8 | 15 ± 6 |
| R5P from T3P and S7P (transketolase) | 71 ± 2 | 78 ± 2 | 70 ± 2 | 66 ± 2 | 70 ± 2 | 62 ± 2 |
| R5P from E4P (transaldolase) | 44 ± 2 | 24 ± 2 | 23 ± 2 | 40 ± 2 | 29 ± 2 | 24 ± 2 |
| Ser originating from Gly and C1-unit | 61 ± 4 | 68 ± 4 | 68 ± 4 | 62 ± 4 | 69 ± 4 | 72 ± 4 |
| Gly originating from CO2 and C1-unit | 10 ± 4 | 13 ± 3 | 13 ± 3 | 6 ± 4 | 12 ± 3 | 10 ± 3 |
| Pep originating from Oaacyt (PepCK) | 0 ± 4 | 0 ± 8 | 0 ± 10 | 2 ± 5 | 0 ± 10 | 5 ± 11 |
| Oaamit originating from Pep | 44 ± 2 | 32 ± 2 | 44 ± 2 | 42 ± 2 | 35 ± 2 | 41 ± 2 |
| Oaamit originating from Oaacyt | n.a. | 43 ± 3 | 55 ± 3 | n.a. | 44 ± 3 | 51 ± 3 |
| Oaacyt originating from Pep | n.a. | 63 ± 3 | 64 ± 4 | n.a. | 66 ± 3 | 66 ± 4 |
| Oaacyt reversibly converted to Fum | 63 ± 11 | 7 ± 5 | 10 ± 5 | 63 ± 11 | 11 ± 4 | 9 ± 4 |
| Flux through malic enzyme, upper bound | 1 ± 4 | n.d. | n.d. | 1 ± 6 | n.d. | n.d. |
| Flux through malic enzyme, lower bound | 1 ± 2 | n.d. | n.d. | 0 ± 3 | n.d. | n.d. |
Origins of metabolic intermediates during growth of P. pastoris in glucose-limited chemostat 13C-labelled cultures at D = 0.1 h-1 at different fractions of oxygen in the chemostat inlet gas. Values for both control and Fab producing strains are given. Ratios highlighted in bold have been used as constraints for metabolic flux analysis. n.a., not applicable; n.d., not determined. See main text for explanation.