Can salivary enzymes function in the acidic environment of stomach?

No, salivary enzymes cannot function in the acidic environment of the stomach. Most salivary enzymes have an optimal pH range between 6 and 7. The pH of the stomach typically ranges from 1 to 3, which is highly acidic. In such an acidic environment, salivary enzymes would undergo denaturation and lose their catalytic activity.

Here's how the acidic environment of the stomach affects salivary enzymes:

Denaturation: The acidic environment causes the protein structure of salivary enzymes to unfold and lose their proper conformation. This process, known as denaturation, disrupts the enzyme's active site and impairs its ability to bind and catalyze reactions.

Inactivation: Once denatured, salivary enzymes lose their catalytic activity and are no longer able to perform their specific biochemical functions. This inactivation is irreversible, meaning that the enzymes cannot regain their activity even if the pH is adjusted back to a more favorable range.

Examples of salivary enzymes and their sensitivity to low pH:

Amylase: Salivary amylase, responsible for breaking down carbohydrates in the mouth, has an optimal pH of around 6.8-7.0. It loses its activity rapidly at pH values below 5.

Lipase: Salivary lipase, involved in initial digestion of dietary fats, has an optimum pH range of around 5.0-6.0. It becomes progressively inactive as the pH decreases below 5.0.

Proteases: Salivary proteases, such as lingual lipase and kallikrein, have optimal pH values around 7.0-8.0. They are quickly inactivated in the acidic environment of the stomach.

In summary, the acidic environment of the stomach prevents salivary enzymes from functioning effectively due to denaturation and inactivation. This is an important physiological mechanism that ensures that salivary enzymes do not interfere with the digestive processes in the stomach, where the breakdown of food requires a different set of enzymes adapted to the acidic conditions.