Temperature

Raising the temperature increases the amount of molecular motion in a system, so the molecules of both substrate and enzyme move around more quickly. This greater motion increases the probability that an enzyme and its substrate will collide and successfully react, so the reaction rate rises with temperature. This continues only up to the enzyme's optimum temperature, the temperature at which its catalytic activity is maximal. Beyond this optimum, further heating begins to disrupt the weak bonds (hydrogen and ionic bonds) that hold the enzyme's precise 3D shape together, causing rapid denaturation; once denatured, the enzyme's active site loses its correct shape and can no longer bind substrate effectively, so the reaction rate falls sharply even though the temperature keeps rising. At the other extreme, very low …