Metabolic robustness is an emergent property of hierarchical network organization in yeast

ABSTRACT Biological systems exhibit intrinsic robustness, allowing cells to sustain growth despite diverse perturbations. We quantified the inherent robustness of the Saccharomyces cerevisiae genome-scale metabolic network by globally perturbing metabolite production fluxes using a hypothetical sink reaction. Among the 317 high-flux active metabolites, excluding macromolecular intermediates and highly connected cofactors, 85% were found to be robust. Of these robust metabolites, more than half (144/269) were overproduced under perturbation compared with minimal-media controls. These metabolites, mapped to a single central metabolic cluster within the metabolic network, were enriched in core biosynthetic pathways and were largely growth-essential, indicating that the network tolerates elevated biosynthetic demand for most key metabolites. Flux- and pathway-level analyses revealed a coordinated adaptive program involving activation of alternative routes at the network periphery and extensive flux redistribution within central metabolism. Central carbon metabolism and oxidative phosphorylation were broadly suppressed, whereas the pentose phosphate, shikimate, and lipid-related pathways were selectively reinforced to support NADPH generation and redox balance. This reorganization establishes an energy-efficient, redox-stabilized metabolic state that underlies system-wide resilience. Together, these findings show that metabolic robustness emerges from a hierarchical network architecture coupling a stable core with flexible peripheral adaptation. This framework explains cellular resilience and offers design principles for engineering robust, damage-resistant metabolic systems. IMPORTANCE In this study, we investigated the intrinsic robustness of the metabolic network and uncovered a structured organization characterized by a conserved central core and a flexible, peripherally rewired subsystem. Our results suggest that this architecture reflects an evolutionary balance between stability and adaptability. By systematically perturbing more than 300 metabolites, we provide comprehensive and consistent evidence supporting the existence of this core–periphery organization. These findings advance our understanding of how metabolic systems maintain functional stability while retaining the capacity for adaptive rewiring.