What is the optimal temperature for enzymes?

The optimal temperature for enzymes is between 20°C and 30°C. Enzyme activity is highest between these temperatures. This is because, at this temperature range, the kinetic energy in the enzyme and substrate molecules is conducive for the maximum number of collisions between them. Enzyme activity decreases at lower temperatures, because the reactants have less kinetic energy at low temperatures, resulting in fewer collisions between them. They become completely inactivated at very low temperatures. As the temperature increases, the kinetic energy of the reactants increases, increasing the likelihood of them colliding into each other with enough energy for a reaction to occur. However, very high temperatures above 45°C alter the shape of the enzyme so it is no longer complementary to its specific substrate. This effect is irreversible and is called denaturation.