5/6/13
The Effects of Pepsin VS. Trypsin in The Digestion of Protein
Introduction
As food is mechanically and chemically digested through our oral cavity then passes through our pharynx and down our esophagus, our food then enters the stomach. The stomach, being the main organ for storage, also helps with breaking down our food, but in order to accomplish that our pancreas helps by excreting an inactive digestive enzyme called pepsinogen. Pepsinogen is the inactive form of the more familiar enzyme called pepsin. In order for pepsinogen to form into pepsin it must first react with the acid HCl breaking it down its layers to reach the active site. To our convenience, HCl is already located in our stomach due excretory glands called parietal cells. As the stomach churns and mixes acid, pepsinogen, and food, pepsin is being created. Pepsin, being its main function to digest protein, is breaking down amino acids into smaller chains of polypeptides until it reaches the small intestine.
Leaving the stomach, the partially broken down food (chyme) passes through the pyloric sphincter then enters the small intestine. This is the site where all terminal digestion of carbohydrates, proteins, and lipids occur including the absorption of amino acids and glucose. Here, the pancreas then excretes a large amount of bicarbonate and an inactive enzyme call trypsinogen which in turn activates to form trypsin which also helps the breaking down of proteins. But compared to pepsin, trypsin does not activate under acidic conditions where chyme has a very low pH and with that, the bicarbonate neutralizes chyme which allows for activation. Additional to that, once trypsin is activated, it itself activates other digestive proteases to aid in digestion. Therefore, digestion and absorption can now occur.
With that said, the digestion of our body proposes a few questions, one being that if we were to take already activated pepsin and trypsin and conduct an