Dissipation in noisy chemical networks: The role of deficiency

TL;DR

This paper investigates how the topological property called deficiency influences the thermodynamic dissipation in noisy chemical networks, revealing that zero deficiency aligns stochastic and deterministic dissipation rates and that noise can reduce dissipation.

Contribution

It demonstrates that deficiency determines the entropic balance in noisy chemical networks and shows how noise can reduce dissipation, a novel insight into cellular metabolism models.

Findings

Dissipation equals deterministic rate only when deficiency is zero.

Noise can reduce dissipation in chemical networks.

Deficiency influences the activation of dissipative pathways.

Abstract

We study the effect of intrinsic noise on the thermodynamic balance of complex chemical networks subtending cellular metabolism and gene regulation. A topological network property called deficiency, known to determine the possibility of complex behavior such as multistability and oscillations, is shown to also characterize the entropic balance. In particular, only when deficiency is zero does the average stochastic dissipation rate equal that of the corresponding deterministic model, where correlations are disregarded. In fact, dissipation can be reduced by the effect of noise, as occurs in a toy model of metabolism that we employ to illustrate our findings. This phenomenon highlights that there is a close interplay between deficiency and the activation of new dissipative pathways at low molecule numbers.