Flux Balance Analysis Within Physiologically Feasible Region

Flux balance analysis (FBA) has emerged as an ef- fective means to quantitatively analyze cell steady-state metabolic behaviors. However, regardless of environmental factors, basal FBA predictions usually represent the theoretical capabilities of the cell which may not be biologically meaningful. This study proposes a physiological state-oriented FBA, which first estimates physiologically feasible region based on powerful 13 C labeling experiment, then FBA is performed within this region. Taking physiological state into account, the proposed strategy is able to produce more biologically meaningful results to accurately characterize cellular metabolic behaviors. The proposed method is further supported by the experimental results of Escherichia coli under oxidative stress condition.