TABLE 3.
13C enrichments in carbon atoms of central metabolites of C. glutamicum WT cultured on CgC mineral medium containing [1-13C]acetate, [5-13C]glucose, or [1-13C]acetate plus unlabeled glucose
| Central metabolite | Carbon atom |
13C enrichment (%)a
|
|||||
|---|---|---|---|---|---|---|---|
| Glucose
|
Acetate
|
Acetate + glucose
|
|||||
| Exp. | Calc. | Exp. | Calc. | Exp. | Calc. | ||
| Pyruvate | C-1 | 3.6 ± 0.2 | 5.7 | 46.8 ± 0.8 | 48.8 | 22.7 ± 1.0 | 23.0 |
| C-2 | 49.3 ± 0.8 | 49.8 | 1.1 ± 0.4 | 1.1 | 1.1 ± 0.4 | 1.1 | |
| C-3 | 3.1 ± 0.2 | 4.2 | 1.1 ± 0.3 | 1.1 | 1.1 ± 0.4 | 1.1 | |
| Oxaloacetate | C-1 | 16.8 ± 1.0 | 16.8 | 49.3 ± 0.3 | 48.8 | 45.5 ± 1.5 | 45.4 |
| C-2 | 35.7 ± 0.8 | 37.6 | 1.1 ± 0.4 | 1.1 | 1.1 ± 0.4 | 1.1 | |
| C-3 | 11.1 ± 0.2 | 11.2 | 1.1 ± 0.4 | 1.1 | 1.1 ± 0.4 | 1.1 | |
| C-4 | 11.8 ± 0.5 | 19.0 | 49.1 ± 0.3 | 50.2 | 46.9 ± 0.6 | 47.0 | |
| 2-Oxoglutarate | C-1 | 11.8 ± 0.6 | 19.0 | 48.1 ± 0.5 | 50.2 | 47.3 ± 0.3 | 47.0 |
| C-2 | 9.9 ± 0.6 | 11.5 | 1.1 ± 0.4 | 1.1 | 1.0 ± 0.4 | 1.1 | |
| C-3 | 34.9 ± 3.0 | 37.5 | 1.1 ± 0.4 | 1.1 | 1.0 ± 0.4 | 1.1 | |
| C-4 | 3.0 ± 0.3 | 4.4 | 1.1 ± 0.4 | 1.1 | 1.0 ± 0.4 | 1.1 | |
| C-5 | 50.8 ± 0.7 | 49.4 | 85.2 ± 4.6 | 79.0 | 82.0 ± 0.8 | 82.0 | |
| 3-Phosphoglycerate | C-1 | 4.1 | 50.8 ± 0.5 | 48.8 | 18.5 ± 2.0 | 19.4 | |
| C-2 | 52.4 ± 0.5 | 51.5 | 1.1 ± 0.4 | 1.1 | 1.1 ± 0.4 | 1.1 | |
| C-3 | 3.2 ± 0.2 | 3.1 | 1.1 ± 0.4 | 1.1 | 1.1 ± 0.4 | 1.1 | |
a
Determined by NMR (Exp.) and calculated (Calc.) by the flux analysis program. Experimental values given are means of two to four determinations. 13C enrichments were deduced from the labeling patterns of alanine and valine for pyruvate, aspartic acid and threonine for oxaloacetate, glutamic acid and arginine for 2-oxoglutarate, and glycine and serine for 3-phosphoglycerate.