Where in the body do you think pepsin and trypsin are most active individually?

In the stomach, chief cells release pepsinogen. HCl activates the zymogen when it's released from parietal cells in the stomach lining. Pepsin functions best in acidic environments and is often found in an acidic environment, particularly those with a pH of 1.5 to 2. The first part of the answer would be that pepsin works only in the stomach, not in the small intestine. Trypsin is produced in the pancreas in the form of inactive zymogen, trypsinogen. It is then secreted into the small intestine, where the enzyme enteropeptidase activates it into trypsin. The optimal operating pH for Trypsin is 8 and about 37°C as optimal operating temperature. The second part of the answer would be that Trypsin works only in the small intestine, actually, it is not present in the stomach.