On structural identifiability of S-system

S-system is a commonly used model for dynamic biological system. However, due to technical limitations, biological reaction networks are often only partially observable, which indicates that not all individuals incorporated in the model can be measured directly. Given a limited amount and quality of experimental data, it cannot be assured that the model structure and parameters can be estimated unambiguously. Hence, it is important to known in what situation the S-system is identifiable and which are not. This knowledge is essential on the construction of model and, indeed, the analysis of the underlying biological system. In this work we shall perform a theoretic discussion on the identifiability of S-system. We shall show that the S-system is identifiable under a set of assumptions. To illustrate the identification performance of S-system, an application on yeast fermentation pathway is conducted.