Physics Commons^™

Impact Of The Solvent Capacity Constraint On E. Coli Metabolism, Alexei Vazquez, Qasim Beg, Marcio Demenezes, Jason Ernst, Ziv Bar-Joseph, Albert-László Barabási, László Boros, Zoltán Oltvai

Albert-László Barabási

Background: Obtaining quantitative predictions for cellular metabolic activities requires the identification and modeling of the physicochemical constraints that are relevant at physiological growth conditions. Molecular crowding in a cell's cytoplasm is one such potential constraint, as it limits the solvent capacity available to metabolic enzymes. Results: Using a recently introduced flux balance modeling framework (FBAwMC) here we demonstrate that this constraint determines a metabolic switch in E. coli cells when they are shifted from low to high growth rates. The switch is characterized by a change in effective optimization strategy, the excretion of acetate at high growth rates, and a …