Law of localization in chemical reaction networks

TL;DR

This paper develops a theory linking the structure of chemical reaction networks in cells to their robustness, predicting how perturbations affect concentrations and fluxes through a general theorem.

Contribution

It introduces a novel theorem connecting network topology with sensitivity patterns, explaining biological robustness and proposing a method to infer networks from experiments.

Findings

Responses exhibit localization and hierarchy patterns.

Network topology underpins biological robustness.

Strategy for inferring networks from measurements.

Abstract

In living cells, chemical reactions are connected by sharing their products and substrates, and form complex networks, e.g. metabolic pathways. Here we developed a theory to predict the sensitivity, i.e. the responses of concentrations and fluxes to perturbations of enzymes, from network structure alone. Responses turn out to exhibit two characteristic patterns, $localization$ and $hierarchy$. We present a general theorem connecting sensitivity with network topology that explains these characteristic patterns. Our results imply that network topology is an origin of biological robustness. Finally, we suggest a strategy to determine real networks from experimental measurements.