Trypsinogen released by the pancreas is converted into active trypsin by

  • A. enterokinase secreted by the wall of the duodenum
  • B. hydrochloric acid from the stomach
  • C. bile salts from the gall bladder
  • D. salivary amylase

Explanation

Enterokinase, an enzyme of the intestinal lining, removes a short peptide from trypsinogen and unmasks its active site, after which trypsin can activate more trypsinogen and other pancreatic precursors as well. Hydrochloric acid is the activator of pepsinogen in the stomach, which is why it is the tempting answer, but it is already neutralised by the time chyme meets pancreatic juice.

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