2.5 - B - Enzyme Rates
The rate of enzyme activity can be quantified by measuring the rate at which reactants are used up or at which the products are created. Within cells and organisms, enzyme activity can be affected by many factors. Each enzyme has optimum conditions under which it functions, so deviating from them affects its activity.
Each enzyme has an optimal temperature that it functions under, which is often related to the organism it is in. As temperatures decrease, so does molecular movement which decreases the rate of collisions between the active site and substrate. When temperature increase, these collisions occur at a faster rate. However, at extreme temperatures the enzymes can denature and lose all functionality.
Reaction catalysis occurs when the substrate and enzyme active site randomly collide. So, as the concentration of substrate molecules increases, the rate at which this collision occurs also increases. However, since only one substrate can occupy an active site at a time, the rate can only increase up to a certain value. This is called the saturation point.