A rigorous approach to steady-state kinetics applied to simple enzyme mechanisms

Steady-state experiments in closed chemical systems measure system properties during evolution on low-dimensional invariant manifolds of the mass-action ordinary differential equations (ODEs) in phase space. Typically, trajectories in the physically realizable part ;;It is sometimes difficult to distinguish mechanisms by straightforward kinetics experiments. The source of this difficulty is analyzed for the Michaelis-Menten mechanism and two schemes in which an inactive enzyme-substrate complex is formed. It is shown that to distinguish these three mechanisms it is mathematically both necessary and sufficient to follow the concentration of the product during an experiment.;It is sometimes possible to choose the parameters of mechanisms with three or more degrees of freedom in such a way that different trajectories attract the flow in different parts of...