A young boy presents with failure to thrive. Biochemical analysis of a aspirate after a meal reveals a deficiency of enteropeptidase (enterokinase). The levels of which digestive enzymes would be affected?
Enteropeptidase formerly called enterokinase activates trypsinogen by limited proteolytic digestion to give trypsin is itself capable of activating trypsinogen, which produces a positive feedback effect. Trypsin also activates chymotrypsinogen (and several other proteolytic enzymes), so deficiency of enteropeptidase results in a severe deficiency of enzymes that digest protein. Amylase aids in the breakdown of starches to oligosaccharides, maltose, and maltotriose. Colipase along with other lipases functions to digest fats. Lactase is a brush-border disaccharidase that hydrolyzes the bond between galactose and glucose in lactose. Pepsin is a proteolytic enzyme secreted in an inactive form (pepsinogen) by the chief cells .of the stomach. Pepsinogen is activated by stomach acid, and so is not dependent on enteropeptidase. Pepsin alone will not replace the activities of other proteolytic enzymes, paly because food does not remain in the stomach for an extended period of time.
Amylase
Colipase
Lactase
Trypsin