Digestion and Absorption of Nutrients
In the stomach, hydrolysis of the protein takes place by the action of the hydrochloric acid secreted there. This denatures the protein and allows the peptides to be attacked. In addition, the acid also activates the enzyme pepsinogen (a zymogen) into its active form of pepsin. This enzyme attacks a range of peptide bonds and, therefore, is able to split the long protein chain into a series of shorter, polypeptide chains.