Question

The graph illustrates the activity level of three common digestive enzymes, across a range of pH values. Which enzyme is likely to be the most active in the acidic environment of the stomach?

A) pepsin
B) trypsin
C) amylase
D) pepsin and trypsin

Answer 1

Pepsinogen, an inactive zymogen, is secreted into gastric juice from both mucous cells and chief cells. Once secreted, pepsinogen is activated by stomach acid into the active protease pepsin, which is largely responsible for the stomach's ability to initiate digestion of proteins.