Question

Name the enzymes for protein digestion in the gastric, pancreatic and intestinal juices, the substrate they digest, and the products of their action.

Answer 1

Hint: Digestion is the breakdown of large insoluble food molecules (polysaccharides, fats, nucleic acids, and proteins) into small water-soluble molecules (monosaccharides, fatty acids, nucleotides, and amino acids) so that they can be easily absorbed into the blood plasma. In certain species, these smaller particles are ingested from the small intestine into the bloodstream.

Complete answer:
Proteins are important nutrients utilized by the body to build cellular structures that serve important functions. The basic building blocks of proteins are very essential to the cells of the human body. The basic building blocks of protein are amino acids and our body uses them as the building of biological substances. So, when we eat something and once we swallow it, enzymes break down the proteins in the food into amino acids.
Protein digestion is not an easy process. A large protein molecule breaks down in the stomach and in the small intestine via a few intermediate stages until it becomes a small amino acid. Through the action of an enzyme called pepsin, the digestion of proteins occurs in the stomach. Pepsin acts on the proteins and forms peptones and proteases in the gastric juice. The proteolytic enzymes present in pancreatic juice (trypsin, chymotrypsin, and carboxypeptidases) act on proteins, peptones, and proteoses and form dipeptides. Dipeptidases present in intestinal juice form amino acids by acting on dipeptides.

Note:
Mechanical digestion of protein starts in the mouth when we first start chewing. Two enzymes, called amylase and lipase, are present in the saliva. They meanly break down carbohydrates and fats.