Table 1.

Description of fluxes and metabolites constituting the flux model of C. glutamicum

FluxConversion of metabolitesaEnzyme reaction(s)b
v1 Glucose-6-P↔fructose-6-PGlucose-6-phosphate isomerase (EC 5.3.1.9)
v2 Fructose-6-P↔2 glyceraldehyde-3-P'sPhosphofructokinase (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/pyruvateGlyceraldehyde-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 (EC1.1.1.44)
v5 2 Pentose-5-P's↔sedoheptulose-7-P + glyceraldehyde-3-PTransketolase (EC 2.2.1.1)
v6 Sedoheptulose-7-P + glyceraldehyde-3-P↔fructose-6-P + erythrose-4-PTransaldolase (EC 2.2.1.2)
v7 Erythrose-4-P + pentose-5-P↔fructose-6-P + glyceraldehyde-3-PTransketolase (EC2.2.1.1)
v8 PEP/pyruvate↔AcCoA + CO2 Pyruvate dehydrogenase complex (EC 1.2.4.1; EC2.3.1.12; EC 1.8.1.4)
v9 AcCoA + malate/oxaloacetate↔isocitrateCitrate 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; EC2.3.1.61; EC 1.8.1.4), succinyl CoA synthetase (EC 6.2.1.5)
v12 Succinate↔malate/oxaloacetateSuccinate dehydrogenase (EC 1.3.5.1), fumarase (EC 4.2.1.2)
v13 Isocitrate + AcCoA↔succinate + malate/oxaloacetateIsocitrate lyase (EC 4.1.3.1), malate synthase (EC 4.1.3.2), succinate dehydrogenase (EC 1.3.5.1), fumarase (EC4.2.1.2)
v14 PEP/pyruvate + CO2↔malate/oxaloacetatePEP 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 (EC1.1.1.40)
  • 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 [EC2.1.1.69; EC 2.7.3.9] for PEP/pyruvate, malate dehydrogenase [EC1.1.1.37] 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).