In general, the rates of enzyme-catalyzed reactions are faster as temperature increases and slower as temperatures decrease below an optimal temperature level. When temperature increases, more molecules have more kinetic energy to react, so reaction speed increases. As temperature decreases, so does the available energy, and then the reaction is slowed.
A variation in temperature as little as 1 or 2 degrees Celsius can increase an enzyme-catalyzed reaction rate by 10 to 20 percent. Raising the temperature 10 degrees increases the activity rate of most enzymes by 50 to 100 percent. There is an exception is when temperatures reach a certain threshold above the optimal temperature level. When this happens, the intermolecular attractions that maintain the shapes of proteins are broken and the enzyme molecule's shape changes. This results in decreased binding of reactants and a significant decrease in enzyme activity. At this point, the enzyme is said to be denatured. Many enzymes are denatured when temperatures exceed 40 to 50 degrees C (104 to 122 F). Extremely cold temperatures also significantly slows reaction rate.
The effect of temperature on the rates of enzyme-catalyzed reactions is exactly why food is refrigerated. A refrigerator's cooler environment slows the enzyme-catalyzed reactions that result in food spoilage. Of course, freezing food slows those reactions even further. Other factors that influence the rates of enzyme-catalyzed reactions include surface area, pH and light.