TABLE 1.
Description of fluxes and metabolites constituting the flux model of C. glutamicum
| Flux | Conversion of metabolitesa | Enzyme reaction(s)b |
|---|---|---|
| v1 | Glucose-6-P↔fructose-6-P | Glucose-6-phosphate isomerase (EC 5.3.1.9) |
| v2 | Fructose-6-P↔2 glyceraldehyde-3-P's | Phosphofructokinase (EC 2.7.1.11), fructose-1,6-bisphosphate aldolase (EC 4.1.2.13), triose phosphate isomerase (EC 5.3.1.1) |
| v3 | Glyceraldehyde-3-P↔PEP/pyruvate | Glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.12), 3-phosphoglycerate kinase (EC 2.7.2.3), phosphoglycerate mutase (EC 2.7.5.3), enolase (EC 4.2.1.11) |
| v4 | Glucose-6-P↔pentose-5-P + CO2 | Glucose-6-phosphate dehydrogenase (EC 1.1.1.49), lactonase (EC 3.1.1.31), 6-phosphogluconate dehydrogenase (EC 1.1.1.44) |
| v5 | 2 Pentose-5-P's↔sedoheptulose-7-P + glyceraldehyde-3-P | Transketolase (EC 2.2.1.1) |
| v6 | Sedoheptulose-7-P + glyceraldehyde-3-P↔fructose-6-P + erythrose-4-P | Transaldolase (EC 2.2.1.2) |
| v7 | Erythrose-4-P + pentose-5-P↔fructose-6-P + glyceraldehyde-3-P | Transketolase (EC 2.2.1.1) |
| v8 | PEP/pyruvate↔AcCoA + CO2 | Pyruvate dehydrogenase complex (EC 1.2.4.1; EC 2.3.1.12; EC 1.8.1.4) |
| v9 | AcCoA + malate/oxaloacetate↔isocitrate | Citrate synthase (EC 4.1.3.7), aconitase (EC 4.2.1.3) |
| v10 | Isocitrate↔oxoglutarate + CO2 | Isocitrate dehydrogenase (EC 1.1.1.42) |
| v11 | Oxoglutarate↔succinate + CO2 | 2-Oxoglutarate dehydrogenase (EC 1.2.4.2; EC 2.3.1.61; EC 1.8.1.4), succinyl CoA synthetase (EC 6.2.1.5) |
| v12 | Succinate↔malate/oxaloacetate | Succinate dehydrogenase (EC 1.3.5.1), fumarase (EC 4.2.1.2) |
| v13 | Isocitrate + AcCoA↔succinate + malate/oxaloacetate | Isocitrate lyase (EC 4.1.3.1), malate synthase (EC 4.1.3.2), succinate dehydrogenase (EC 1.3.5.1), fumarase (EC 4.2.1.2) |
| v14 | PEP/pyruvate + CO2↔malate/oxaloacetate | PEP carboxylase (EC 4.1.1.31), PEP carboxykinase (EC 4.1.1.32), pyruvate carboxylase (EC 6.4.1.1), oxaloacetate decarboxylase (EC 4.1.1.3), malic enzyme (EC 1.1.1.40) |
a
Pentose-5-phosphate combines ribose-5-phosphate, ribulose-5-phosphate, and xylulose-5-phosphate. P, phosphate; AcCoA, acetyl-CoA.
b
Treating PEP and pyruvate, malate and oxaloacetate, and ribose-5-phosphate, ribulose-5-phosphate, and xylulose-5-phosphate as single pools precludes the assignment of fluxes for enzyme reactions interconverting these metabolites (pyruvate kinase [EC 2.7.1.40] and the PEP:glucose-phosphotransferase system [EC 2.1.1.69; EC 2.7.3.9] for PEP/pyruvate, malate dehydrogenase [EC 1.1.1.37] for malate/oxaloacetate, and ribose-5-phosphate isomerase [EC 5.3.1.6] and ribulose-5-phosphate epimerase [EC 5.1.3.1] for pentose-5-phosphates).