Trypsinogen is an inactive enzyme of pancreatic juice. An enzyme, enterokinase, activates it. Which tissue/ cells secrete this enzyme?/ How is it activated?

Trypsinogen is an inactive enzyme of pancreatic juice, it is activated by an enzyme, enterokinase.

Enterokinase is secreted by the intestinal mucosa.

The Trypsinogen is activated by Enterokinase into active trypsin.