Effect of Temperature and pH on Enzymes

• As we increase the temperature, the activity of the enzyme increases (faster reaction) due to the enzyme and substrate moving faster leading to more collisions per second between the substrate and active site.
• At a certain temperature, the enzyme is working at the fastest possible rate. This is called the optimum temperature, however as it is increased further past the optimum, the activity of the enzyme rapidly decreases to zero.
• At high temperatures, the enzyme molecule vibrates and the shape of the active site changes, therefore the substrate can no longer fit perfectly into the active site. The active site is now 'denatured'.
• The enzyme has an optimum pH, where the activity is maximum. If this pH is made more acidic/alkaline then the activity drops to 0 due to the active site being denatured because of conditions.
• Not all enzymes work at the same pH, some are optimised at a different pH.