The Effect of pH on Enzyme Activity pH is a measure of the concentration of hydrogen ions in a solution. The higher the concentration of hydrogen ions, the lower the pH. Most enzymes work effectively over a narrow pH range. A change in pH above or below this range significantly reduces the rate of enzyme reaction. Changes in pH lead to the breakdown of the ionic bonds that hold the tertiary structure of the enzyme in place. The enzyme begins to lose its functional form, notably that of the active site, so that the substrate no longer fits in, we say that the enzyme is denatured. Changes in pH also affect the charges of the amino acids within the active site, so the enzyme will not be able to form an enzyme-substrate complex. The pH at which an enzyme catalyzes a reaction at maximum rate is called optimal pH. This can vary greatly from pH 2 for pepsin to pH 9 for pancreatic lipase. 3[IMAGE][IMAGE]Conclusion=== =======Looking at the results, I can conclude that when the pH was 3 and 5, no oxygen was produced, therefore no reaction took place . This was because the pH had a high hydrogen ion content, which caused the ionic bonds that hold the tertiary structure of the enzyme to break. The enzyme has lost its functional form, particularly the active site form, so the substrate does not