High-throughput metabolic flux analysis based on gas chromatography-mass spectrometry derived 13C constraints

C-13-constrained flux balancing analysis based on gas chromatography-mass spectrometry data is presented here as a simple and robust method for the estimation of intracellular carbon fluxes. In this approach, the underdetermined system of metabolite balances deduced from stoichiometric relations and measured extracellular rates is complemented with C-13 constraints from metabolic flux ratio analysis. Fluxes in central carbon metabolism of exponentially growing Escherichia coli were estimated by C-13-constrained fiux balancing from three different C-13-labeled glucose experiments. The best resolution of the network was achieved using C-13 constraints derived from [U-C-13]glucose and [1-C-13]glucose experiments. The corresponding flux estimate was in excellent agreement with a solution that was independently obtained with a comprehensive isotopomer model. This new methodology was also demonstrated to faithfully capture the intracellular flux distribution in E. coli shake flasks and 1-ml deep-well microtiter plates. Due to its simplicity, speed, and robustness, C-13-constrained metabolic flux balancing is promising for routine and high-throughput analysis on a miniaturized scale. (C) 2003 Elsevier Inc. All rights reserved.