Enzymes catalyze reactions. They bind substrates, lower activation energies and increase the rates at which products are formed. However, if there is not enough substrate available, the active site of the enzyme will be empty most of the time and the enzyme will idle. On the other hand, it there is excess substrate, the active site of the enzyme will always have molecules of substrate bound in it, and all the extra substrate will not be reacting.
In this first biosimulation exercise you will investigate the effect that changing the substrate concentration has on the rate of the reaction, and determine how much substrate is necessary for the enzymes to be working at maximum efficiency all the time.