Which pancreatic enzyme is activated in the duodenum by enterokinase?

• A. Chymotrypsin
• B. Trypsin
• C. Amylase
• D. Lipase

Answer: (B)

Enteropeptidase in the duodenum cleaves trypsinogen to form active trypsin, kick-starting a proteolytic activation cascade. Once trypsin is active, it then converts other pancreatic zymogens—such as chymotrypsinogen to chymotrypsin and procarboxypeptidases to carboxypeptidases—into their active forms, enabling protein digestion. Amylase and lipase do not rely on this activator; amylase is secreted in an active form and lipase functions as an active enzyme in digestion. So, the enzyme activated directly by enterokinase in the duodenum is trypsin.