System identification of biomolecular circuits is a challenging problem, including due to the nonlinearities that are often present in them. The extent to which these nonlinearities contribute to the overall behaviour of the biomolecular circuit is unclear. Here, we address this issue for simple biomolecular circuit models by exploiting the properties of broadband random phase multisine excitations. We analysed the classical models of a two-state signaling system, an enzymatic signaling system, and of a transcriptional feedback circuit for the presence of nonlinear distortions at certain parametric settings and studied their dependence on the input parameters. These results should help the modeller in quantifying the effect of nonlinearities and assessing the validity of the linear models at a particular operating condition.
- System identification
- Biomolecular system