Predicted change in the steady-state rate of protein synthesis and its relaxation time. Graphs illustrating the predicted change in the steady-state rate of protein synthesis (left), and its relaxation time, i.e., the time needed to recover from a perturbation to the steady state value (right). Four curves are presented. The black ones are for the wild-type cap structure, which is modeled by k1 = k2. The red ones are for the modified structure, when k1 <<k2. The main conclusion from the left graph is that if microRNA acts on a late initiation step, diminishing k2, then its effect is not measurable unless k2 is very strongly suppressed (as reported in ). The main conclusion from the right graph is that the effect of microRNA can be measurable in this case if one looks at dynamical features such the relaxation time.