On the role of conserved moieties in shaping the robustness and production capabilities of reaction networks

TL;DR

This paper presents an analytical study of how conserved moieties influence the robustness and production capabilities of reaction networks, revealing that conservation laws confer system flexibility despite growth constraints.

Contribution

It introduces a solvable model demonstrating the impact of stoichiometric conservation laws on metabolic network robustness and growth, supported by analytical results.

Findings

Conserved pools lead to stationary maximal growth flux states.

Stoichiometric constraints increase robustness and flexibility.

Optimal flux volume remains finite under conservation laws.

Abstract

We study a simplified, solvable model of a fully-connected metabolic network with constrained quenched disorder to mimic the conservation laws imposed by stoichiometry on chemical reactions. Within a spin-glass type of approach, we show that in presence of a conserved metabolic pool the flux state corresponding to maximal growth is stationary independently of the pool size. In addition, and at odds with the case of unconstrained networks, the volume of optimal flux configurations remains finite, indicating that the frustration imposed by stoichiometric constraints, while reducing growth capabilities, confers robustness and flexibility to the system. These results have a clear biological interpretation and provide a basic, fully analytical explanation to features recently observed in real metabolic networks.