Question

What is the role of hydrochloric acid in the stomach?

Answer 1

Hydrochloric acid provides an acidic medium for the action of protein digesting enzymes which are present in their inactive form in the gastric juice. For example pepsin. Pepsin is an enzyme that breaks protein into peptides. Pepsinogen is the inactivated form of pepsin which in the presence of HCl forms active pepsin. Due to its high acidity, it also helps to kill microbes entering the stomach along with food.