What are examples of enzymes sensitive to pH changes?

Examples of enzymes sensitive to pH changes include pepsin, trypsin, and catalase.

Pepsin is an enzyme that operates in the stomach, where the pH is typically very acidic, around 2. This enzyme is responsible for breaking down proteins into smaller peptides, a crucial step in digestion. If the pH of the stomach were to increase significantly, becoming less acidic, pepsin would not function as effectively. This is because the shape of the enzyme, which is crucial for its function, is sensitive to pH changes.

Trypsin is another enzyme involved in digestion, but it operates in the small intestine where the pH is much more neutral, around 7.5. Trypsin continues the process started by pepsin, breaking down peptides into individual amino acids. If the pH in the small intestine were to decrease, becoming more acidic, trypsin would not be able to function properly. This is because, like pepsin, the shape of trypsin is sensitive to pH changes.

Catalase is an enzyme found in nearly all living organisms exposed to oxygen. It functions to catalyse the decomposition of hydrogen peroxide to water and oxygen. Catalase has one of the highest turnover rates for all enzymes; one catalase molecule can convert millions of molecules of hydrogen peroxide to water and oxygen each second. Catalase is most effective at a near-neutral pH, but its activity can be affected by changes in pH. If the pH becomes too acidic or too alkaline, the enzyme can lose its shape and functionality.

In summary, enzymes are sensitive to changes in pH because their function depends on their shape, which can be altered by changes in pH. This is why the pH of different parts of the body is carefully regulated, to ensure that enzymes can function optimally.