Which of the following enzymes are involved in protein digestion?
Peptidases and Proteases
Proteases
Lipases
Amylases
Peptidases
The correct answer and explanation is:
The correct answer is Peptidases and Proteases.
Explanation:
Protein digestion begins in the stomach and continues in the small intestine. Proteins are large macromolecules made up of amino acids linked by peptide bonds. These peptide bonds need to be broken down in order to absorb the individual amino acids into the bloodstream. Two classes of enzymes that facilitate this process are proteases and peptidases.
- Proteases (also called proteinases) are enzymes that break down proteins by cleaving the peptide bonds between amino acids. They are the main enzymes responsible for protein digestion. The protease enzyme pepsin is secreted in the stomach and begins the breakdown of proteins by breaking down large proteins into smaller peptides. As the partially digested protein moves to the small intestine, other proteases such as trypsin and chymotrypsin are secreted by the pancreas. These enzymes further break down the smaller peptides into even smaller ones.
- Peptidases are a specific type of protease that further break down small peptides into individual amino acids. Peptidases are found on the surface of epithelial cells lining the small intestine. They cleave the remaining peptide bonds between the amino acids, resulting in free amino acids that can be absorbed by the intestinal cells.
Other enzymes mentioned:
- Lipases are involved in fat digestion, not protein digestion. They break down fats (lipids) into fatty acids and glycerol.
- Amylases are enzymes that break down carbohydrates, particularly starch, into simpler sugars such as maltose. They do not play a role in protein digestion.
In summary, both proteases and peptidases are critical to the process of protein digestion, helping to break down complex proteins into smaller peptides and ultimately into absorbable amino acids.