This model is the reaction sequence SEQFB, a model pathway of a branched system with sequential feedback interactions found in bacterial amino acid synthesis. Its steady state is presented in Fig 4.

The model is described in:

**METAMOD: software for steady-state modelling and control analysis of metabolic pathways on the BBC microcomputer.**

JHS Hofmeyr and KJ van der Merwe, *Comput Appl Biosci*
1986 2:243-9; PubmedID: 3450367

Abstract:

METAMOD, a BBC microcomputer-based software package for steady-state modelling and control analysis of model metabolic pathways, is described, The package consists of two programs. METADEF allows the user to define the pathway in terms of reactions, rate equations and initial concentrations of metabolites. METACAL uses one of two algorithms to calculate the steady-state concentrations and fluxes. One algorithm uses the current ratio of production and consumption rates of variable metabolites to adjust iteratively their concentrations in such a way that they converge towards the steady state. The other algorithm solves the roots of the system equations by means of a quasi-Newtonian procedure. Control analysis allows the calculation of elasticity, control and response coefficients, by means of finite difference approximation. METAMOD is interactive and easy to use, and suitable for teaching and research purposes.

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