METATOOL: for studying metabolic networks

Motivation: To reconstruct metabolic pathways from biochemical and/or genom e sequence data, the stoichiometric and thermodynamic feasibility of the pa thways has to be tested. This is achieved by characterizing the admissible region of flux distributions in steady state. This region is spanned by wha t can be called a convex basis. The concept of 'elementary flux modes' prov ides a mathematical tool to define all metabolic routes that are feasible i n a given metabolic network. In addition, we define 'enzyme subsets' to be groups of enzymes that operate together in fixed flux proportions in all st eady states of the system. Results: Algorithms for computing the convex basis and elementary modes dev eloped earlier are briefly reviewed A newly developed algorithm for detecti ng all enzyme subsets in a given network is presented All of these algorith ms have been implemented in a novel computer program named METATOOL, whose features are outlined here. The algorithms are illustrated by an example ta ken from sugar metabolism.