Some compounds may slow down enzymatic reactions, thus acting as inhibitors. There are two kinds of inhibitors: competitive and noncompetitive ones. The competitive inhibitor binds to the same site of enzyme that is occupied by substrate. Noncompetitive inhibitor interacts with an enzyme in such a way to change its shape. As a result an active site of enzyme does not "fit" the substrate anymore. Both kinds of inhibition decreases a number of catalytic enzyme molecules, therefore the rate of enzymatic reaction reduces. A group of switches in the lower part of a window of interactive model enables to choose a kind of inhibition. An animation is operated by the "Start"/"Stop" and the "Reset" buttons.