Dynamic response to step-change in production of X. a). This figure shows how a step change in production rate of X (starting from 0) imposed at t = 0, affects the concentration of all different components. Here, K
>> 1. Note that eventually the concentration of free X also reaches a steady state. b) When the timescale of the lower-affinity interaction (interaction of X with B) is lengthened, the higher-affinity interaction saturates at earlier times, and the lower-affinity interaction saturates at later times. c) When the timescale of the higher-affinity interaction (interaction of X with A) is lengthened, the order in which the complexes are formed can be reversed, so that the lower-affinity interaction saturates at an earlier time than the higher-affinity interaction. Note that in this case the total amount of X in the system finally is clearly greater than the total of A and B put together, so that eventually, most of A and B are present in complexed form. (d) The case where the lower affinity component is faster is shown. Here a sudden change in production of X is imposed so that the total X does not exceed the total amount of A and B. Here we see that at early times (see inset) B takes up most of the X, while at longer times, the concentration of the complex BX gradually decreases and that of AX eventually increases.