[Modelling of the regulatory system of tryptophan biosynthesis using generalized threshold models]

A mathematical model of the tryptophan biosynthesis regulatory system (TBRS) in Escherichia coli has been constructed and studied by the method of generalized threshold models. The system includes the tryptophan operon, the operon producing aporepressor and multienzyme chain of tryptophan synthesis. The kinetic curves for molecular components of the system (mRNA, proteins, tryptophan) are obtained by means of computer calculations using mathematical model of the TBRS. The dynamics of normal and mutant regulatory systems of tryptophan biosynthesis and the system with cloned blocks have been analysed. Functioning of the following mechanisms regulating tryptophan biosynthesis is studied: feed-back inhibition of enzyme activity, repression and attenuation of the tryptophan operon transcription. It is shown that the method of generalized threshold models reflects the dynamics of a molecular genetic regulatory system more completely than the method of threshold models.