Stochastic Control of Metabolic Pathways

Abstract: I will discuss the effect of extrinsic noise in metabolic networks. In particular I will 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 the presence of extrinsic noise, control coefficients are shown to incorporate its effect through an explicit dependency on the noise intensity. This leads naturally to the introduction of the concept of 'control by noise' as a way of tuning the systemic behaviour of metabolisms. I argue that this framework holds for intrinsic noise too, when time-scale separation is present in the system, and define the noise propagation problem in metabolic networks.