Where does the conversion of trypsinogen to trypsin occur?

The conversion of trypsinogen to trypsin occurs primarily in the lower duodenum. This process is crucial for the digestive system, as trypsin is an active enzyme that plays a key role in the digestion of proteins. Trypsinogen is an inactive precursor (or zymogen) produced by the pancreas and secreted into the small intestine. When it reaches the small intestine, it encounters enterokinase, an enzyme found in the intestinal mucosa, which activates trypsinogen by cleaving it to form trypsin.

The lower duodenum is significant because it is the primary site where pancreatic enzymes, including trypsinogen, are activated to facilitate digestion after the chyme from the stomach mixes with bile and pancreatic juices. Understanding this conversion process and its location is essential for comprehending how protein digestion begins and progresses in the digestive tract.