Question

In Flux Balance Analysis, what condition must the stoichiometric matrix satisfy at the steady state to ensure the mass balance of all intracellular metabolites?

Accepted Answer

In Flux Balance Analysis, the condition required for the steady state is that the product of the stoichiometric matrix and the flux vector must equal zero, represented by the equation S times v equals zero. The stoichiometric matrix, denoted as S, is a grid where each row represents a specific intracellular metabolite and each column represents a specific biochemical reaction, with the values inside indicating the number of molecules consumed or produced by each reaction. The flux vector, denoted as v, represents the rate at which each reaction occurs within the cell. The steady state condition assumes that the concentration of internal metabolites remains constant over time because the total rate of production for each metabolite exactly balances the total rate of consumption. If a metabolite is produced by one reaction at a rate of five units per second, it must be consumed by other reactions at a combined rate of five units per second, resulting in a net change of zero. Mathematically, this means the sum of all stoichiometric coefficients for a metabolite multiplied by their respective reaction fluxes must equal zero across all reactions in the system. If this condition is not met, the metabolite would either accumulate indefinitely or be depleted, which contradicts the fundamental biological assumption that the cell maintains a stable internal environment during the timeframe of the analysis.

Home → All Courses → Engineering and Technology Courses → Synthetic Biology Engineering → Flashcard

In Flux Balance Analysis, what condition must the stoichiometric matrix satisfy at the steady state to ensure the mass balance of all intracellular metabolites?