The dynamics of a species is represented by a differential equation with the structure:
where Xi represents one of the nd variables of the model (metabolite concentrations, protein concentrations or levels of gene expression). j represents the nf biochemical processes affecting the dynamics of the species. On the other hand, μ {\displaystyle \mu } ij (stoichiometric coefficient), γ {\displaystyle \gamma } j (rate constants) and fjk (kinetic orders) are two different kinds of parameters defining the dynamics of the system.
The principal difference of power-law models with respect to other ODE models used in biochemical systems is that the kinetic orders can be non-integer numbers. A kinetic order can have even negative value when inhibition is modeled. In this way, power-law models have a higher flexibility to reproduce the non-linearity of biochemical systems.
Models using power-law expansions have been used during the last 35 years to model and analyze several kinds of biochemical systems including metabolic networks, genetic networks and recently in cell signalling.
Books:
Scientific articles:
Biochemical Systems Theory, an introduction. https://www.hindawi.com/journals/isrn/2013/897658/ ↩
Athel Cornish-Bowden, Metabolic control analysis FAQ, website 18 April 2007. /wiki/Athel_Cornish-Bowden ↩