Metabolic Flux & Stoichiometry

A simple metabolic network with 4 metabolites and 5 reactions. Sliders adjust enzyme activities (rate constants). Steady-state fluxes are computed in real time.

Steady-state fluxes loading…
v₁ (input): 1.0
v₂ (A→B): 1.0
v₃ (B→C): 1.0
v₄ (C→D): 1.0
v₅ (branch): 0.3

Flux Balance Analysis

At steady state, for each metabolite: Σ(production fluxes) = Σ(consumption fluxes). This is the stoichiometric constraint Sv=0 where S is the stoichiometry matrix. The network here: A is input, branches to B and a side product, B→C→D (output). Michaelis-Menten kinetics: vᵢ=kᵢ[substrate]/(Kₘ+[substrate]). The width of flow arrows is proportional to computed flux. Bottleneck reactions (low rate constants) limit the pathway — the law of the minimum.