title: Global self-regulation of the cellular metabolic structure.
abstract: BACKGROUND
  Different studies have shown that cellular enzymatic activities are able to self-organize spontaneously, forming a metabolic core of reactive processes that remain active under different growth conditions while the rest of the molecular catalytic reactions exhibit structural plasticity. This global cellular metabolic structure appears to be an intrinsic characteristic common to all cellular organisms. Recent work performed with dissipative metabolic networks has shown that the fundamental element for the spontaneous emergence of this global self-organized enzymatic structure could be the number of catalytic elements in the metabolic networks.
  
  
  RESULTS
  In order to investigate the factors that may affect the catalytic dynamics under a global metabolic structure characterized by the presence of metabolic cores we have studied different transitions in catalytic patterns belonging to a dissipative metabolic network. The data were analyzed using non-linear dynamics tools: power spectra, reconstructed attractors, long-term correlations, maximum Lyapunov exponent and Approximate Entropy; and we have found the emergence of self-regulation phenomena during the transitions in the metabolic activities.
  
  
  CONCLUSIONS
  The analysis has also shown that the chaotic numerical series analyzed correspond to the fractional Brownian motion and they exhibit long-term correlations and low Approximate Entropy indicating a high level of predictability and information during the self-regulation of the metabolic transitions. The results illustrate some aspects of the mechanisms behind the emergence of the metabolic self-regulation processes, which may constitute an important property of the global structure of the cellular metabolism.
authors.affiliation: Department of Mathematics, University of the Basque Country, Vizcaya, Spain. mtpmadei@ehu.es
authors.forename: Ildefonso M
authors.initials: IM
authors.lastname: De la Fuente
authors.forename: Fernando
authors.initials: F
authors.lastname: Vadillo
authors.forename: Alberto Luís
authors.initials: AL
authors.lastname: Pérez-Samartín
authors.forename: Martín-Blas
authors.initials: MB
authors.lastname: Pérez-Pinilla
authors.forename: Joseba
authors.initials: J
authors.lastname: Bidaurrazaga
authors.forename: Antonio
authors.initials: A
authors.lastname: Vera-López
mesh_terms: D000465:Algorithms; D000495:Allosteric Site; D000818:Animals; D001669:Biochemical Phenomena; D002384:Catalysis; D002477:Cells / Q000378:metabolism; D005786:Gene Expression Regulation; D006801:Humans; D053858:Metabolic Networks and Pathways; D008954:Models, Biological; D015233:Models, Statistical; D017711:Nonlinear Dynamics