Figure 4. Enzymes with high essentiality and low variability that are robust to the ratio of objective function's components.

Reactions with high essentiality and low variability were identified through a set of 1000 objective functions with nonequivalent ratios among function components. As panel (A) shows, reactions obeying both criteria (red on black regions) were plotted over the 1000 realizations. In each realization, those enzymes that obey the in silico criteria were denoted in black; all others in white. The percentage of times reactions obeyed the computational criteria are depicted in panel (B). Robust enzymes relevant to this study (excluding transporters, exchange and demand reactions) were labeled in red. EX, DM and Sink denote exchange, demand and sink reactions in the cytoplasm [c] and mitochondria [m] compartments.