Issue
EPL
Volume 85, Number 3, February 2009
Article Number 38007
Number of page(s) 6
Section Interdisciplinary Physics and Related Areas of Science and Technology
DOI http://dx.doi.org/10.1209/0295-5075/85/38007
Published online 13 February 2009
EPL, 85 (2009) 38007
DOI: 10.1209/0295-5075/85/38007

On the role of conserved moieties in shaping the robustness and production capabilities of reaction networks

A. De Martino1, C. Martelli2 and F. A. Massucci2

1   CNR/INFM (SMC), Dipartimento di Fisica, Sapienza Università di Roma - p.le A. Moro 2, 00185 Roma, Italy, EU
2   Dipartimento di Fisica, Sapienza Università di Roma - p.le A. Moro 2, 00185 Roma, Italy, EU

andrea.demartino@roma1.infn.it

received 30 October 2008; accepted in final form 20 January 2009; published February 2009
published online 13 February 2009

Abstract
We study a simplified, solvable model of a fully connected metabolic network with constrained quenched disorder to mimic the conservation laws imposed by stoichiometry on chemical reactions. Within a spin-glass type of approach, we show that in the presence of a conserved metabolic pool the flux state corresponding to maximal growth is stationary independently of the pool size. In addition, and at odds with the case of unconstrained networks, the volume of optimal flux configurations remains finite, indicating that the frustration imposed by stoichiometric constraints, while reducing growth capabilities, confers robustness and flexibility to the system. These results have a clear biological interpretation and provide a basic, fully analytical explanation to features recently observed in real metabolic networks.

PACS
87.18.-h - Biological complexity.
75.10.Nr - Spin-glass and other random models.
87.18.Vf - Systems biology.

© EPLA 2009