What happens to the rate of an enzyme-catalysed reaction when temperature increases? And when pH changes?

As temperature increases, the molecules involved in the reaction gain kinetic energy, increasing the chances of collision between the substrate molecules and the active sites of the enzymes, a step that is necessary for catalysis. Therefore, the rate of an enzyme-catalysed reaction increases with temperature, up to an optimum temperature. However, if the temperature continues to increase past this point, the enzymes become denatured and lose their function as a catalyst, thus the reaction stops.

Each enzyme has an optimum pH at which the maximum rate of the reaction is reached, and a narrow interval of tolerance within which the reaction occurs at a lower rate. Enzymes are very sensitive to pH changes, since they cause variation to the superficial charges at their active sites, modifying their shape and difficulting interation with the substrates. Therefore, a change in pH will reduce the rate of an enzyme-catalysed reaction and may cause it to stop if the new pH doesn't fall within the interval at which the enzyme can function.