Pepsin
Pepsin is an enzyme that catalyzes the action of breaking proteins into their simplest forms also known as amino acids. Primarily, it is active in the stomach and therefore has been termed one of the most vital digestion catalysts.
The presence of pepsin in many parts of the alimentary tract is highly important to digestive health.
Its improper activity or overactivity is sometimes associated with diseases of gastroesophageal reflux disease (GERD), and more recent evidence in the field of science and medicine exists for laryngopharyngeal reflux (LPR).
It is necessary to find out part played by pepsin in the human organism, setting focus on the functions, interactions, and implications of pepsin for health, with related diseases and potential treatments.
Nature and Function of Pepsin
Pepsin is an enzyme that catalyzes the breakdown of proteins into smaller polypeptides and amino acids, rendering these compounds absorbable in the small intestine.
Pepsin is secreted by chief cells lining the stomach in an inactive form called pepsinogen.
Upon exposure to this acidic environment in the stomach, produced mainly by hydrochloric acid, pepsinogen is converted into its active form, pepsin.
Pepsin works optimally in a slightly acidic environment that is naturally occurring in the stomach, wherein pH can be anywhere between 1.5 and 3.5.
It acts to break down proteins into smaller peptides in this slightly acidic environment, thereby preparing them for further digestion and absorption in the small intestine.
The body would have great difficulty extracting necessary amino acids from dietary proteins for overall nutrition and health without the action of the enzyme.
Digestive Action of Pepsin
Pepsin is mainly assigned the role of hydrolyzing proteins in the stomach. This enzyme acts to hydrolyze peptide bonds mostly if they include an aromatic amino acid such as phenylalanine, tryptophan, and tyrosine.
Subsequent digestion takes place by other enzymes such as trypsin and chymotrypsin in the small intestine, once pepsin has split the proteins into smaller peptides.
Pepsin constitutes a very crucial enzyme for the digestion of proteins from foods that comprise of meat, dairy products, and legumes.
The activity of pepsin in the stomach is important to initiate protein digestion, which is then completed in the small intestine.
If pepsin is absent, the entire process of digestion would severely be impaired, which would cause serious malabsorption of nutrients.
The medium for starting digestion is gastric juice, which contains pepsin and hydrochloric acid.
The acidity of the stomach is responsible for the activation of pepsinogen into pepsin and, along with this acidity, offers the best conditions for the functioning of pepsin.
This digestive mixture starts the digestion of ingested proteins into smaller components.
In a healthy stomach, pepsin is activated only within its own acid environment. In such cases, however, pepsin and the acidic stomach contents may reflux into the esophagus, thereby causing discomfort and possibly damaging the lining of the esophagus, which in turn can cause diseases like gastroesophageal reflux disease (GERD).
Gastroesophageal Reflux Disease and Pepsin
One of the most common gastrointestinal diseases is GERD, an abbreviation for gastroesophageal reflux disease.
GERD is a disease characterized by the flow backward of acidic stomach contents, which include pepsin, into the esophagus. Pepsin is an enzyme that is to be found in the stomach.
When it reaches the esophagus, an organ that is not accustomed to an acidic environment or to proteolytic enzymes, irritation followed by inflammation and tissue damage results.
In GERD, pepsin renders the lining of the esophagus vulnerable to being degraded in the presence of acidic gastric secretions.
The signs and symptoms may include heartburn, regurgitation, and pain in the chest.
One can become susceptible to secondary complications such as Barrett's esophagus, a condition predisposing a person to increased risk of development of cancer of the esophagus.
Laryngopharyngeal Reflux (LPR) and Pepsin
Another equally common condition associated with pepsin is laryngopharyngeal reflux (LPR), during which stomach content progresses into the larynx and the pharynx-the upper airway and throat.
In LPR, the irritation and inflammation caused by the presence of pepsin in the throat result in symptoms such as sore throat, hoarseness, coughing, and swelling in the throat.
LPR, conversely, may often be asymptomatic of one of the classic symptoms of heartburn. On that basis alone, it sometimes can become much more difficult to diagnose than GERD.
Pepsin in saliva is a significant marker for diagnosing LPR, because one would not typically find the enzyme in a normal upper airway. Determination of salivary pepsin may aid in confirming diagnosis of LPR, especially in patients with unexplained throat or voice symptomatology.
Pepsin and Implications in Reflux Disease
Pepsin is a central component in reux disease, GERD and LPR, because being present in the esophagus or throat is abnormal; it causes intense, damaging pain over time.
Treatments for reflux disease, GERD and LPR commonly involve reducing the acidity of the stomach environment, which lowers the activation and activity of pepsin.
Common treatments for reflux disease include the use of proton pump inhibitors (PPIs) and H2 blockers, both of which decrease stomach acid production.
This means that reducing acid levels through these treatments reduces the activation of pepsin from its inactive form, pepsinogen, helping to minimize damage from acid reflux.
However, recent studies, such as those by Dettmar PW, have indicated that reducing stomach acid may well prove inadequate for inactivation of pepsin since it appears to survive in its active form in most non-acidic environments making treatment strategies much more complicated.
Pepsin in Saliva: A Diagnostic Marker
Prior to this discussion, it has been established that the existence of salivary pepsin is one of the classic signs of the existence of laryngopharyngeal reflux.
Normally, pepsin should only exist in the stomach so the existence of such in saliva points to an abnormal refluxing of content from the stomach upward into the airways.
Then, salivary pepsin would then be a diagnostic tool in the disease especially if the classical signs of reflux are not apparent.
Some researches suggest that even the testing of pepsin in saliva can be a better use than the typical pH monitoring that aims to detect acid reflux and not the pepsin itself.
Since pepsin can function well even in less acidic conditions, detection might give a clearer indication about the presence of the disease and even a hint of its severity.
Pepsin Digestion of Proteins
Pepsin's major role in digestion is the cleavage of proteins into small peptides. This is an essential function for the body to absorb because amino acids are the fundamental building blocks of proteins.
These amino acids are required by the body for a wide variety of biological functions, such as the repair of muscles, production of enzymes, and synthesis of hormones.
Pepsin makes it possible for the body to obtain those vital amino acids through the breakdown of complex proteins in the stomach.
The enzyme works best in an acidic environment of the stomach, where hydrochloric acid not only activates pepsinogen into pepsin but also assists with the process of protein denaturation, making the proteins available for enzymatic cleavage.
Other enzymes further break the smaller peptides apart. These include trypsin and chymotrypsin in the small intestine.
This step-by-step degradation assures complete digestion down to the amino acid level, which can be absorbed into the bloodstream for use by the body.
Pepsin and Its Inhibitors
As pepsin is involved in reflux diseases, it becomes interesting to read how different mechanisms have been developed for the inhibition of its activity.
Traditionally, PPIs in the treatment of reflux depend upon the reduction of acid within the stomach; that logically diminishes the activation of pepsinogen into pepsin.
However, pepsin becomes active even at low acid levels; thus, researchers are searching for better inhibitors.
Other research efforts focused on designing pepsin-specific inhibitors or coatings that would prevent the activity of the enzyme in the esophagus or throat.
The inhibitors would neutralize pepsin in the presence of reflux, thus minimizing the possible damage.
Moreover, lifestyle changes, like altering food and diet intake, will reduce the activity and flow of pepsin.
Reducing intake of food that triggers acid production prevents the increase in pressure within the stomach due to more frequent, smaller consumption of meals, thereby reducing reflux episodes.
Pepsin and Contemporary Research
Recent research continues to study the mechanisms of pepsin and its function in digestion as well as in disease.
Of particular interest is the relationship between the pepsin molecule and the microbiome, where the balance of gut bacteria could influence how well pepsin works and its contribution to GERD and LPR.
In addition, the research on new treatment targets that target pepsin in the esophagus and throat will eventually provide relief for patients with reflux disease.
Diagnostic techniques are also becoming better with time to enhance the accuracy of reflux condition diagnoses by even detecting pepsin in saliva.
Conclusion
Pepsin is an important digestive enzyme primarily responsible for degradation of proteins into smaller peptides and amino acids.
Though the stomach's activity will determine adequate digestion, the presence of pepsin in the esophagus or throat can cause significant health problems, as evidenced by GERD and LPR conditions.
Understanding functions and implications of pepsin is a requirement for managing digestive health, as well as being an area of importance in the treatment of reflux diseases. Further research into pepsin and its inhibitors.
* Medical Disclaimer - The following information is for educational purposes only. No information provided on this website, including text, graphic, and images, are intended as substitutes for professional medical advice. Please consult with your doctor about specific medical advice pertaining to your condition(s).
