It was observed that the rate of catalase activity was highest under conditions of neutral pH. Its activity in alkaline and acidic conditions was extremely low. That meant the optimum pH for catalase was pH 7. At that pH, the concentration of hydrogen ions and hydrogen ions affected the active site of the protein in a way that gave it a shape that was most complementary to the shape of the substrate. At acidic and alkaline conditions, the enzyme probably gained and lost hydrogen ions thereby interfering with its structure. The altered conformation affected the structure of the enzyme’s active site hence affecting its ability to bind the substrate (hydrogen peroxide). Consequently, a low rate of reaction was seen.
It was also realized that catalase exhibited maximum activity at a temperature of 40 oC. Therefore, it could be deduced that the optimum temperature for catalase was 40 oC. The optimum temperature meant that there were sufficient collisions between the enzyme and substrates at that point (“Factors Affecting Enzyme Activity†par. 2). Those collisions led to the formation of enzyme-substrate complexes that were ultimately converted to products. At low temperatures (4 oC), the activity of catalase was low because the low temperatures inactivated the enzyme by lowering its kinetic energy (Hillsborough Community College 18). In addition, low temperatures reduced the number of collisions between the enzyme and the substrate hence lowering the reaction rate. High temperatures, on the other hand, resulted in low enzymatic activity because they denatured the protein by permanently altering its conformation. High temperatures destroyed important bonds such as hydrogen bonds and Van der Waals forces that were responsible for holding the protein structure in place. Consequently, the active sites could not match the structures of their substrates.
