How Are Proteins Digested?

How Are Proteins Digested?

A protein molecule comprises a chain of bound amino acids, bent into a complex globular form. The digestion of the protein in the food you eat involves deploying the protein chain and then unlinking the amino acids it contains. These amino acids, once your body absorbs them, are incorporated into the new proteins that your body synthesizes as necessary. The digestion of the protein occurs in the stomach and small intestine with the help of enzymes secreted by the pancreas.


After chewing and swallowing food, the low pH of stomach acid begins to denature, or to develop the proteins you consume. This development is important, since it allows digestive enzymes to access the bonds that hold individual amino acids together. Gastric juice in the stomach contains a protease or enzyme-degrading protein, called pepsin, pepsin and will bind to the large, heavy molecule of the protein, separating it into smaller pieces of proteins known as peptides. Microorganisms that can inadvertently consume your food usually die in the presence of your stomach acid, and the proteins they contain bind to your food protein group in the digestive process.


Although no protein digestion occurs in your pancreas, this organ is essential in the process of digestion. The pancreas secretes a buffer that contains bicarbonate that serves to neutralize your gastric contents when they move out of your stomach and into the small intestine. This is important because, with the exception of pepsin, your digestive proteases and peptidases are not active because of the low pH of stomach acid. The digestive enzymes trypsin, chymotrypsin and carboxypeptidase, secreted by pancreatic cells, are poured into the small intestine.

Small intestine

Now enter a neutral pH of about 7, the mixture of peptides in the small intestine is ready for further degradation. Your pancreatic enzymes work to cleave the mixture of peptides into smaller peptides and finally into individual amino acids. Each digestive enzyme works by separating specific amino acids from the short peptide chains until a pool of free amino acids remains. The walls of your small intestine consist of structures called villi, with a collection of folds that greatly increases the surface area of ​​the small intestine. The pool of individual amino acids is absorbed through your intestinal villi, where they enter the bloodstream and then to your cells as needed.


The small intestine includes the duodenum, the ileum, and the jejunum.Protein digestion occurs in the duodenum, while absorption takes place in the ileum and jejunum. Health problems that affect any part of your small intestine can affect your ability to digest and absorb dietary proteins.

Video Tutorial: Protein Digestion and Absorption.

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