Network with a component exhibiting structurally constrained concentration.

(a) Reaction diagram that includes seven reactions, R1–R7, and three components, A–C. (b) stoichiometric matrices associated with substrates, N−, and products, N+, for the network in (a). Reaction R7 lacks one substrate molecule of B in comparison to R2, since and for every i ≠ 2. Reactions R3 and R5 share the same substrate components with same stoichiometry, and hence their fluxes are fully coupled under the assumption of mass action kinetic. Reaction R3 is fully coupled to reaction R4, as are reactions R5 and R6. (c) Component B exhibits structurally constrained concentration from the ODEs of components A and C. The network exhibits different positive steady states with changing rate of reaction R1.