Properties of Random Complex Chemical Reaction Networks and Their Relevance to Biological Toy Models

TL;DR

This paper studies large random chemical reaction networks with thermodynamically consistent kinetics, revealing their tendency to produce a specific chemical and demonstrating a toy model of proto-cell growth with homeostasis.

Contribution

It introduces a model of random conservative chemical networks with realistic kinetics and shows their potential to sustain proto-cell growth with homeostasis.

Findings

Networks preferentially produce a specific chemical under nutrient flux.

Proto-cell model exhibits sustainable growth with sufficient nutrient metabolism.

Chemical networks show similar qualitative behavior regardless of kinetic details.

Abstract

We investigate the properties of large random conservative chemical reaction networks composed of elementary reactions endowed with either mass-action or saturating kinetics, assigning kinetic parameters in a thermodynamically-consistent manner. We find that such complex networks exhibit qualitatively similar behavior when fed with external nutrient flux. The nutrient is preferentially transformed into one specific chemical that is an intrinsic property of the network. We propose a self-consistent proto-cell toy model in which the preferentially synthesized chemical is a precursor for the cell membrane, and show that such proto-cells can exhibit sustainable homeostatic growth when fed with any nutrient diffusing through the membrane, provided that nutrient is metabolized at a sufficient rate.