Pepsin Amino Acid Sequence

Pepsin is effective for the breaking down of protein in the body. So we will be looking at pepsin amino acid sequence. As well as some applications of pepsin.


If you know a bit about science then you would most likely have an idea what pepsin is. It is an enzyme in the body that has the function of breaking down proteins in the body into smaller amino acids. This enzyme is produced by cells in our body, known as chief cells. These cells are located in the lining of the stomach. Its basic function of pepsin is for digestion. This enzyme can be found in humans as well as other animals. For today, we will be looking at the pepsin amino acid sequence. 

Have you ever heard that enzymes are proteins? Well, if you haven’t, this is a good thing to bear in mind. All enzymes are proteins. Another thing you should bear in mind is that all proteins are made up of different amino acids. That means that pepsin is made up of amino acids since it’s an enzyme that is made up of proteins. Let’s take a closer look at the actions of pepsin in the body. As well as some of the important things that you must bear in mind when it comes to pepsin. 

Pepsin Amino Acid Sequence 

This is an aspartic protease that helps break down protein in the digestive system. It breaks down protein into smaller peptides that way they are easily absorbed by the body. This enzyme happens to be one of the main proteases that are effective in the digestive system. This enzyme is produced by the stomach and its work is digesting the protein that we eat. 

The precursor of pepsin happens to be pepsinogen. It is released by chief cells located in the lining of the intestine. Let’s now take a look at the structure of this enzyme. 

Pepsinogen is made up of about 44 amino acids. While pepsin is made up of about 326 amino acids. Pepsin is known to be less stable when compared to pepsinogen when in a weak alkaline or neutral environment. But when pepsinogen is exposed to gastric acid in the stomach it is broken down and then activated to pepsin. 

Pepsin is a monomer which means it is a chain protein. It is made up of two folding domains that are similar but they are separated with the help of a deep cleft. A catalytic site is formed when the two domains come together. Each of the domains has 2 residues of aspartic acid. They are Asp 215 and Asp32. 

Pepsin is known to be very active when it is an acidic environment at a temperature of about 37-42 degrees Celsius. At about a pH of 2.0, it is most effective and when it is anything above pH 6.5 it is no longer active. 

Physiological Effects 

Pepsin is known to be among the main causes of injury in the mucosal layer of the larynx and pharynx thus causing reflux. When pharyngeal reflux happens pepsin tends to stay in the larynx and the pharynx for quite some time. The thing with pepsin is that when it is in a neutral environment it tends to be inactive. But when it is exposed to an incident of acid reflux this causes reactivation of the enzyme. 

When there is reactivation pepsin becomes active. Then the mucosa of the larynx is exposed to the pepsin. This results in a reduction of the expression of certain proteins that protect the larynx. Thus making the laryngeal mucosa more susceptible to injury. 

There are also times that pepsin when in an environment that isn’t acidic or weakly acidic can still cause injury. What happens is that pepsin is being internalized by receptor-mediated endocytosis in the upper respiratory tract of the patient. When this happens the cells ingest the enzyme and then they are stored in vesicles at a low pH. This is how pepsin gains its activity back. 

In the end, this leads to inflammation. And then there are signs and symptoms of the reflux. That’s why when upper airway specimens are checked, the presence of pepsin is indicative of pharyngeal reflux. This is considered to be a sensitive and specific test. 

One inhibitor of pepsin is pepstatin. It has strong effects on inhibiting pepsin. The thing though is that pepstatin can’t bind covalently to pepsin. That is why the inhibitory action of pepstatin is reversible. Another inhibitor of pepsin is sucralfate. 


There are a few applications of pepsin in the food industry. This is used in the making of cheese. It is part of the pancreatic curd, it condenses and twists when making cheese. 

Another thing that pepsin is used is that it helps modify gelatin and soybean protein. It also helps provide whipping qualities. It is also used for modification of plant protein used in making pre-cooked cereals and non-dairy snacks for making instant cereals. 

It can also be used in the making of seasonings for food and beverages. It is used for preparing hydrolysates for both plant and animal protein. Another interesting use of pepsin is in the leather industry. It is used for removing residual tissue and hair from the leather. Also, it is used to get back silver from photographic films that have been abandoned. It does this by digesting the layer of gelatin where the silver is being stored. 

From these uses listed above, you can tell that pepsin is sure not only useful in the human body. It is also effective in our world today. And knowing these applications would give you an idea of what you can use pepsin for. 

Pepsin in the body is quite important. It helps with the breaking down of protein so that the nutrients can be absorbed by the body. With enough pepsin in the body digestion of protein would be a smooth ride. With too much, it could cause an ulcer. And when it is too little this could lead to a problem as well. As the best thing is having the right amount of pepsin in the body for proper digestion. Well, that’s all we have for you concerning the pepsin amino acid sequence. 

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