Flows in complex biochemical networks: Role of low degree nodes

TL;DR

This paper reviews how low degree metabolites in biochemical networks underpin both essential reactions and functional modules, enabling predictions of drug targets and regulatory modules from network structure.

Contribution

It reveals that essentiality and modularity in metabolic networks stem from low degree metabolites, providing a structural basis for predicting drug targets and modules.

Findings

Low degree metabolites are key to essential reactions.

Structural network analysis can predict drug targets.

Modularity arises from low degree nodes.

Abstract

Metabolic networks have two properties that are generally regarded as unrelated: One, they have metabolic reactions whose single knockout is lethal for the organism, and two, they have correlated sets of reactions forming functional modules. In this review we argue that both essentiality and modularity seem to arise as a consequence of the same structural property: the existence of low degree metabolites. This observation allows a prediction of (a) essential metabolic reactions which are potential drug targets in pathogenic microorganisms and (b) regulatory modules within biological networks, from purely structural information about the metabolic network.