Question

In details described the enzymes and involve in digestiion of protein in the stomach

Answer 1

The digestion of food starts in the buccal cavity. The mechanical activity of tongue involving chewing, tearing, and biting helps make food particles more accessible to enzymes present in saliva and later in the stomach and intestine. Digestion of proteins begins in the stomach. When food reaches into the stomach, it faces the acidic nature of the stomach (pH- 1 to 2). In this high acidic environment, the protein loses its three-dimensional structure and gets unfolded. The lining of the stomach contains some gastric glands which release gastric juice upon entry of food in the stomach. This gastric juice contains enzyme pepsin, which is released in an inactive form pepsinogen and is activated by the presence of hydrochloride acid. Pepsin is a proteolytic enzyme and degrades protein into peptones and proteoses which are smaller fragments of a large protein. In infants, another proteolytic enzyme rennin is found which is secreted as pro rennin and is converted into an active form by HCl. Rennin acts on milk casein and converts it to paracaseinate.

Later the fragmented peptones and peptides enter duodenum, the first segment of small intestine where further break down of protein occur to yield amino acids. The major proteolytic enzymes of duodenum are trypsin and chymotrypsin which is released from pancreatic juice into small intestine.