Predicted flux distributions during aerobic respiratory growth with succinate. Map of R. sphaeroides central carbon metabolism showing flux distributions predicted by iRsp1095 during aerobic growth with succinate. All fluxes are in mmol/gDW h. The fluxes in black are those predicted for the wild type cells, while those in red are predictions made for the ΔpntAB deletion strain. Reactions with no flux values are predicted to have a zero flux. To improve accuracy of predictions, fluxes were constrained using publicly available genome-wide expression data from wild type cells grown aerobically on succinate (see Methods). Green arrows indicate the predicted NADPH generating reactions under these conditions. The entry point of some other carbon sources utilized by R. sphaeroides are also shown (blue boxes). It should be noted that the predicted fluxes shown represent only one of many optimal solutions from the FBA solution space. Also note that R. sphaeroides does not possess a homolog of 6-Phosphogluconate dehydrogenase, which links the pentose phosphate pathway (PPP) with the Entner-Doudoroff (ED) pathway in some other organisms. TCA – tricarboxylic acid; G6P – Glucose 6-phosphate; F6P – Fructose 6-Phosphate; F1,6P – Fructose 1,6-bisphosphate; G3P – Glyceraldehyde 3-phosphate; DHAP – Dihydroxyacetone phosphate; 6PGL – phosphoglucono-δ-lactone; 6PG – 6-Phosphogluconate; KDPG – 2-Keto-3-deoxy-6-phosphogluconate; PEP – Phosphoenolpyruvate; Pyr – Pyruvate; A-CoA – Acetyl-CoA; CIT – Citrate; ISOCIT – Isocitrate; 2-OG – 2-oxoglutarate; SUCC-CoA – Succinyl CoA; SUCC – Succinate; FUM – Fumarate; MAL – Malate; OAA – Oxaloacetate; AA-CoA – acetoacetyl-CoA; 3HB-CoA – 3-hydroxy butyryl-CoA; Cr-CoA – crotonyl-CoA; EM-CoA – Ethylmalonyl-CoA; MM-CoA – β-methylmalyl-CoA; PROP-CoA – Propionyl-CoA; PHB – Polyhydroxybutyrate.