Temperature
Chemical reactions go faster as the temperature increases because molecules move faster and collide more often and more violently.
At low temperature, enzyme activity is slow due to the slower movement of particles so there is less collisions between the substrate and the enzyme active site. As the temperature increases, the rate of activity increases as molecules move faster and collide more often until a optimum temperature is reached. At the optimum temperature, the activity of the enzyme is the highest. At temperatures above the optimum, the rate of enzyme activity slows because the enzyme denatures as there is enough energy to break bonds holding the enzyme and its active site in its special shape. At very high temperatures, the enzyme is completely denatured so activity stops completely.
