The protein-digesting enzyme secreted by the stomach wall in case of mammals is called

In mammals, the stomach wall contains specialized cells that secrete gastric juice to initiate protein digestion. Specifically, chief cells in the gastric lining release an inactive zymogen called pepsinogen [3]. When this precursor comes into contact with hydrochloric acid (HCl) secreted by parietal cells, it is converted into its active form, pepsin [3]. Pepsin is the principal protein-digesting enzyme of the stomach, functioning as an endopeptidase that breaks down complex proteins into smaller peptides and polypeptides [2][3]. While other enzymes like trypsin and chymotrypsin also digest proteins, they are secreted by the pancreas into the small intestine rather than the stomach wall [1][2]. Amylase is primarily involved in carbohydrate digestion in the mouth and small intestine, and chitinase breaks down chitin, which is not the primary protein-digesting function of the mammalian stomach.

Sources

1. [3] https://www.ncbi.nlm.nih.gov/books/NBK537005/
2. [2] https://www.sciencedirect.com/topics/biochemistry-genetics-and-molecular-biology/digestive-enzyme
3. [1] Science-Class VII . NCERT(Revised ed 2025) > Chapter 9: Life Processes in Animals > Small Intestine > p. 126