Pepsin converts proteins into smaller chains of amino acids called peptides or peptones and some free amino acids.
This partial digestion is also the crucial first step in protein breakdown and allows the nutrients to be absorbed fully later in the small intestine.
The reason why pepsin works best at pH 2 is because a pH 2 environment is essential for active site activation and protein denaturation.
Pepsin is an aspartic protease, which relies on 2 critical amino acids in it's active site, (aspartate residues).
And at pH 2, one of these aspartate residues is properly protonated (bound to a hydrogen ion) and the other is deprotonated, which creates the perfect structural and chemical state to bind and cleave proteins.
And for the protein denaturation, the highly acidic stomach environment helps to unfold and denature the dietary proteins.
Unraveling the tight protein structures exposes the peptide bonds so that pepsin can efficiently break them down.
And by contrast, in the higher pH of the small intestine, pepsin becomes inactive and is eventually neutralized.
The benefits of pepsin are optimal gut health, efficient digestion and nutrient absorption.
Pepsin allows for efficient protein digestion as pepsin dismantles the complex proteins in meats, eggs and dairy into smaller fragments so that the small intestine can easily absorb them.
And by breaking down proteins, the pepsin helps to unbind and release critical micronutrients, like vitamin B12, which allows your body to properly utilize them.
And pepsin also reduces symptoms of poor digestion, like bloating, gas indigestion and constipation, especially in people with low stomach acids.
The amino acids that are released by pepsin action also trigger the release of secondary digestive hormones such as gastrin, that stimulate pancreatic secretions and promote smooth gastric emptying.
The organ that releases pepsin is the stomach, most specifically the specialized cells in your stomach lining called gastric chief cells that secrete the pepsin in an inactive, form called pepsinogen.
The inactive release of pepsin in the form of pepsinogen prevents it from digesting the body's own proteins.
Pepsin is activated through hydrochloric acid or HCI, where parietal cells in your stomach produce HCI, which create a highly acidic environment (pH 1.5 to 2.5).
And when the pepsinogen mixes with your stomach acid, it's converted into active pepsin.
And then active pepsin breaks down dietary proteins into smaller and easily absorbable peptides.
Pepsin is the powerful digestive enzyme in the stomach that helps to break down the proteins in food that you eat like dairy, eggs, meat etc into smaller and usable building blocks.
The stomach lining releases pepsin in an inactive, safe form that is called pepsinogen, which prevents your stomach from digesting itself.
When you eat food and the food enters your stomach, glands then release strong hydrochloric acid (stomach acid).
This highly acidic environment then instantly converts the inactive pepsinogen into active pepsin.
And once active, the pepsin then acts like molecular scissors, snipping large and complex protein chains into smaller chains called peptides.
And these smaller pieces then travel to the small intestine, where they are then fully broken down into amino acids and absorbed.
Without pepsin, the body would still successfully digest protein and survive, but the initial stage of your digestion in your stomach would also slow down greatly.
Although pepsin is your primary stomach enzyme that is responsible for chopping large dietary proteins into smaller fragments, the pepsin is not actually essential to maintain life.
The vast majority of protein that is broken down occurs after the food leaves your stomach and enters your stomach and pepsin is only responsible for between 10 percent to 20 percent of total protein digestion.
And without the pepsin, the pancreas releases powerful alternative enzymes that are known as proteases, which include carboxypeptidase, chymotrypsin and trypsin.
These enzymes easily pick up the slack of the pepsin, breaking down whole proteins into the absorbable acids that the body needs.
Although because protein would not get a head start in digestion in the stomach, your digestive system would also have to work harder without the pepsin.
And heavy protein rich meals like steak for example, would take much longer to break down without the pepsin.
If you have low pepsin, what happens is your body struggles to break down the dietary proteins.
The inefficiency of too little pepsin, triggers a cascade of digestive issues, nutritional deficits and physical discomfort.
When you have too little pepsin, it leads to poor digestion, increased infection risk and nutritional deficiencies.
With too little pepsin, large protein molecules are not cleaved into absorbable peptides.
This also causes food to linger in your stomach, fermenting and producing gas.
And pepsin and stomach acid are also required to extract and absorb critical nutrients like iron, vitamin B12, calcium and magnesium.
Stomach acid also acts as the primary barrier against pathogens.
And low levels of pepsin and stomach acid makes your GI tract more vulnerable to bacterial overgrowth, like SIBO and infections.
Common symptoms of too little pepsin include.
Fatigue, brain fog and muscle cramps.
Weak, brittle nails or hair that thins over time.
Having undigested food particles in your poop.
Experiencing feeling of extreme fullness just shortly after starting a meal.
And bloating, gas and belching, especially after eating meals heavy in protein.
If your stomach stopped producing pepsin, your body would struggle to digest proteins.
This would lead to severe gastrointestinal distress, bloating, and potential long-term malnutrition, although your small intestine would attempt to compensate using pancreatic enzymes to break the proteins down.
Pepsin is the enzyme responsible for initiating the digestion of proteins into smaller peptide chains.
Without the pepsin, intact proteins can move into the large intestine where they ferment, causing significant gas, bloating, and discomfort.
Because protein isn't efficiently pre-digested in the stomach, your body may also fail to absorb essential amino acids over time, leading to potential muscle loss and malnutrition.
Pepsin also functions in a highly acidic environment driven by hydrochloric acid (HCl).
Together, this acid-enzyme combination plays a vital role in destroying harmful bacteria and pathogens ingested with your food.
Without pepsin and optimal acidity, your risk for gastrointestinal infections spikes.