Genome-Scale In Silico Models of E. coli Have Multiple Equivalent Phenotypic States: Assessment of Correlated Reaction Subsets That Comprise Network States

Reaction usage in optimal flux distributions. (A) shows for each reaction in the metabolic network, what fraction of the optimal flux distributions utilize this reaction (f_opt). The reactions are then rank-ordered by frequency of use in optimal flux distributions. Each reaction in the model was previously classified into one of 30 subsystems. (B) shows for each subsystem how many reactions belong to that subsystem (No. Rxns) and what fraction of these reactions are: never used (f_opt = 0), used in less than 25% of the solutions (0 < f_opt < 0.25), used in between 25% and 50% of the solutions (0.25 < f_opt < 0.5), used in between 50% and 75% of the solutions (0.5 < f_opt < 0.75), used in between 75% and 100% of the solutions (0.75 < f_opt < 1), and used in all of the solutions (f_opt = 1). The individual fractions are shaded according to value: less than 0.1 is white, between 0.1 and 0.5 is light gray, and larger than 0.5 is dark gray.