title: Global self-organization of the cellular metabolic structure.
abstract: BACKGROUND
  Over many years, it has been assumed that enzymes work either in an isolated way, or organized in small catalytic groups. Several studies performed using "metabolic networks models" are helping to understand the degree of functional complexity that characterizes enzymatic dynamic systems. In a previous work, we used "dissipative metabolic networks" (DMNs) to show that enzymes can present a self-organized global functional structure, in which several sets of enzymes are always in an active state, whereas the rest of molecular catalytic sets exhibit dynamics of on-off changing states. We suggested that this kind of global metabolic dynamics might be a genuine and universal functional configuration of the cellular metabolic structure, common to all living cells. Later, a different group has shown experimentally that this kind of functional structure does, indeed, exist in several microorganisms.
  
  
  RESULTS
  Here we have analyzed around 2.500.000 different DMNs in order to investigate the underlying mechanism of this dynamic global configuration. The numerical analyses that we have performed show that this global configuration is an emergent property inherent to the cellular metabolic dynamics. Concretely, we have found that the existence of a high number of enzymatic subsystems belonging to the DMNs is the fundamental element for the spontaneous emergence of a functional reactive structure characterized by a metabolic core formed by several sets of enzymes always in an active state.
  
  
  CONCLUSIONS
  This self-organized dynamic structure seems to be an intrinsic characteristic of metabolism, common to all living cellular organisms. To better understand cellular functionality, it will be crucial to structurally characterize these enzymatic self-organized global structures.
authors.affiliation: Departamento de Matemáticas, Facultad de Ciencia y Tecnología, Universidad del País Vasco, Vizcaya, Spain.
authors.forename: Ildefonso M
authors.initials: IM
authors.lastname: De La Fuente
authors.forename: Luis
authors.initials: L
authors.lastname: Martínez
authors.forename: Alberto L
authors.initials: AL
authors.lastname: Pérez-Samartín
authors.forename: Leire
authors.initials: L
authors.lastname: Ormaetxea
authors.forename: Cristian
authors.initials: C
authors.lastname: Amezaga
authors.forename: Antonio
authors.initials: A
authors.lastname: Vera-López