Item

Abstract

Complex metabolic networks are characterized by a great number of elements and many regulatory loops. The description of these networks with mathematical models requires the definition of functional units, which group together several cellular processes. The presented approach is based on the idea that cellular functional units may directly be assigned to mathematical modeling objects. Since the proposed modeling objects have defined in- and outputs, they can be connected with other modeling objects until eventually the whole metabolism is covered. This modular approach guarantees a high transparency for biologist as well as for engineers. Three criteria are introduced to demarcate functional units. The criteria consider physiological pathways, the organization of the corresponding genes and the observation that cellular systems can be structured into units showing a hierarchy of signal transduction and processing. As an example the carbon catabolic reactions in Escherichia coli are discussed as members of a functional unit catabolism. (C) 2000 Academic Press. [accessed 2014 October 16]