Stochastic Control of Metabolic Pathways

TL;DR

This paper extends metabolic control analysis to include extrinsic noise, showing how external fluctuations influence control coefficients and systemic behavior in metabolic networks.

Contribution

It introduces a stochastic framework for metabolic control analysis incorporating extrinsic noise effects and defines new elasticities and response coefficients.

Findings

Control coefficients depend explicitly on noise intensity.

Summation and Connectivity Theorems remain valid under noise.

Control by noise can tune metabolic system behavior.

Abstract

We study the effect of extrinsic noise in metabolic networks. We introduce external random fluctuations at the kinetic level, and show how these lead to a stochastic generalization of standard Metabolic Control Analysis. While Summation and Connectivity Theorems hold true in presence of extrinsic noise, control coefficients incorporate its effect through an explicit dependency on the noise intensity. New elasticities and response coefficients are also defined. Accordingly, the concept of control by noise is introduced as a way of tuning the systemic behaviour of metabolisms. We argue that this framework holds for intrinsic noise too, when time-scale separation is present in the system.