SUMOFLUX: A Generalized Method for Targeted 13C Metabolic Flux Ratio Analysis
Fig 2
Comparison of SUMOFLUX and analytic formula estimates for flux ratios in E. coli central carbon metabolism.
From left to right: a schematic representation of the flux ratio; density plot representing SUMOFLUX estimates versus the true flux ratios for in silico data; comparison of the SUMOFLUX and analytic formula estimates for the experimental data; density plot representing analytic formula estimates versus the true flux ratios for in silico data. Vertical error bars in the third panel represent [10–90%] SUMOFLUX prediction quantiles, horizontal error bars represent standard deviation provided with the analytic formula estimate. (a) Glycolysis versus PPP. (b) Pyruvate fraction from the E-D pathway. (c) PEP fraction from gluconeogenesis. (d) Pyruvate fraction from the malic enzyme flux. (e) Oxaloacetate fraction from anaplerosis from PEP. Ratios (a)-(c) were estimated from [1-13C] glucose experiment, ratios (d) and (e) were estimated from 20% [U-13C] and 80% naturally labeled glucose experiment. 6PG– 6-phosho-D-gluconate; αKG– α-ketoglutarate; AcCoA—acetyl-CoA; E-D—Entner-Doudoroff pathway; F6P –fructose-6-phosphate; Fum—fumarate; G6P –glucose-6-phosphate; Gox—glyoxylate; ICT—isocitrate; KDPG—2-Keto-3-deoxy-6-phosphogluconate; MAE—mean absolute error; Mal—malate; PCC—Pearson correlation coefficient; PEP—phosphoenolpyruvate; PGA—phosphoglycerate; PPP—pentose phosphate pathway.