what participates in protein digestion within the stomach?
Digestion of Proteins in the Stomach. Two of the substances secreted by the stomach, HCl (hydrochloric acid) and pepsinogen, interact to create pepsin, an enzyme that plays a very important role in protein digestion.The process that takes place when proteins are disintegrated by the enzymes is called hydrolysis.igestion of Proteins in the Stomach. Two of the substances secreted by the stomach, HCl (hydrochloric acid) and pepsinogen, interact to create pepsin, an enzyme that plays a very important role in protein digestion.