Which enzymes are pancreatic proteases that continue dietary protein digestion in the small intestine?

• A. They are pancreatic proteases including trypsin, chymotrypsin, and carboxypeptidases that continue digestion of proteins in the small intestine.
• B. They are digestive enzymes that break down starch.
• C. They digest fats in the stomach.
• D. They are produced by the gallbladder.

Answer: (A)

Pancreatic proteases are the enzymes that finish protein digestion in the small intestine. The pancreas releases proteases such as trypsin, chymotrypsin, and carboxypeptidases into the duodenum, and they are secreted as inactive precursors that are activated in the intestinal lumen (trypsinogen and the others activated by enterokinase, with trypsin then helping activate the rest). Trypsin and chymotrypsin cut internal peptide bonds, creating shorter peptides, while carboxypeptidases remove amino acids from the C-terminus to yield free amino acids. This activity continues the breakdown of dietary proteins after the stomach’s pepsin begins proteolysis, taking over in the more alkaline environment of the small intestine. The other options aren’t enzymes that digest proteins in the small intestine: starch digestion is done by amylases, fat digestion by lipases, and bile from the gallbladder assists fat emulsification rather than acting as an enzyme.