Pepsin is a protein-degrading or proteolytic enzyme in the digestive system. Pepsin is released by the cells in the stomach. This enzyme degrades food proteins into peptides to facilitate absorption. Pepsin is a digestive protease, a member of the aspartate protease family. During the process of digestion, pepsin severs the links between particular types of amino acids, collaborate to break down dietary proteins into their components, i.e., peptides and amino acids, which can be readily absorbed by the intestinal lining. Pepsin is most efficient in cleaving peptide bonds between hydrophobic and preferably aromatic amino acids such as phenylalanine, tryptophan, and tyrosine.
Pepsin is expressed as a pro-form zymogen, pepsinogen, whose primary structure has an additional 44 amino acids. In the stomach, chief cells release pepsinogen. This zymogen is activated by hydrochloric acid (HCl), which is released from parietal cells in the stomach lining. The hormone gastrin and the vagus nerve trigger the release of both pepsinogen and HCl from the stomach lining when food is ingested. Hydrochloric acid creates an acidic environment, which allows pepsinogen to unfold and cleave itself in an autocatalytic fashion, thereby generating pepsin (the active form). Pepsin cleaves the 44 amino acids from pepsinogen to create more pepsin.
Pepsin is most active in acidic environments between 37°C and 42°C. Accordingly, its primary site of synthesis and activity is in the stomach (pH 1.5 to 2). Pepsin exhibits maximal activity at pH 2.0 and is inactive at pH 6.5 and above, however pepsin is not fully denatured or irreversibly inactivated until pH 8.0. The stability of pepsin at high pH has significant implications on disease attributed to laryngopharyngeal reflux. Pepsin remains in the larynx following a gastric reflux event. At the mean pH of the laryngopharynx pH = 6.8 pepsin would be inactive but could be reactivated upon subsequent acid reflux events resulting in damage to local tissues.
Pepsin is one of the primary causes of mucosal damage during laryngopharyngeal reflux. Pepsin remains in the larynx pH 6.8 following a gastric reflux event. While enzymatically inactive in this environment, pepsin would remain stable and could be reactivated upon subsequent acid reflux events. Exposure of laryngeal mucosa to enzymatically active pepsin, but not irreversibly inactivated pepsin or acid, results in reduced expression of protective proteins and thereby increases laryngeal susceptibility to damage.
Pepsin may also cause mucosal damage during weakly acidic or non-acid gastric reflux. Weak or non-acid reflux is correlated with reflux symptoms and mucosal injury. Under non-acid conditions (neutral pH), pepsin is internalized by cells of the upper airways such as the larynx and hypopharynx by a process known as receptor-mediated endocytosis. Upon cellular uptake, pepsin is stored in intracellular vesicles of low pH at which its enzymatic activity would be restored. Pepsin is retained within the cell for up to 24 hours. Such exposure to pepsin at neutral pH and endoyctosis of pepsin causes changes in gene expression associated with inflammation, which underlies signs and symptoms of reflux, and tumor progression. This and other research implicates pepsin in carcinogenesis attributed to gastric reflux.
Pepsin is found in the saliva of persons suffering from gastro-esophageal reflux, which causes persistent corroding of buccal mucosa, leading to deep ulcers of mouth cavity.
Commercial pepsin is extracted from the glandular layer of hog stomachs. It is a component of rennet used to curdle milk during the manufacture of cheese. Pepsin is used for a variety of applications in food manufacturing: to modify and provide whipping qualities to soy protein and gelatin, to modify vegetable proteins for use in nondairy snack items, to make precooked cereals into instant hot cereals, and to prepare animal and vegetable protein hydrolysates for use in flavoring foods and beverages. It is used in the leather industry to remove hair and residual tissue from hides and in the recovery of silver from discarded photographic films by digesting the gelatin layer that holds the silver. Pepsin was historically an additive of chewing gum. It also gave name to Pepsi-Cola, originally formulated with pepsin and cola nuts.
PEPSINUM is the homeopathic preparation prepared by potentizing PEPSIN. In potentized forms, it contains MOLECULAR IMPRINTS of pepsin molecules. Potentized PEPSINUM above 12C could be used in the treatment of GERD, to heal the mucosal damage caused laryngopharyngeal reflux. It is also useful in the treatment of gastric ulcers, esophagitis, esophageal ulcerations and strictures, esophageal and laryngeal carcinoma etc.
Personally, I have regularly used PEPSINUM 30 successfully in the treatment of GASTRITIS, GASTRIC ULCER and ESOPHAGITIS and deep ulcers of buccal cavity.