Enterokinase acts in:

Enteropeptidase (also called enterokinase) is an enzyme produced by cells of the duodenum and is involved in digestion in humans and other animals. Enteropeptidase conves trypsinogen (a zymogen) into its active form trypsin, resulting in the subsequent activation of pancreatic digestive enzymes. Absence of enteropeptidase results in intestinal digestion impairment.