Chymotrypsin - What Is It Important For?

What is the chymotrypsin?

Chymotrypsin is an enzyme that plays a role in digestion in the human body. As an enzyme, it has the task of breaking down proteins from food and breaking them down into small components - so-called oligopeptides - which can then be absorbed in the intestine. Chymotrypsin is produced in the pancreas and, alongside other digestive enzymes such as trypsin, pepsin or carboxypeptidases, plays an important role in the absorption of proteins.

For more information about carboxypeptidases, read our article: Carboxypeptidase

Function of chymotrypsin

Chymotrypsin is an enzyme from the pancreas (pancreas), which is responsible for the chopping and splitting of proteins ingested with food. The proteins are converted into so-called oligopeptides (Composition of less than 10 amino acids) so that they can then be more easily absorbed through the mucous membrane in the small intestine and brought into the circulation. In this way, the body can absorb important components from protein-containing foods such as nuts, whole-grain bread, poultry or fish. This in turn is important so that the body can use it to build its own proteins. These include, for example, hormones and antibodies for the immune system, but also proteins for blood clotting, muscle building, hair and nails.

Chymotrypsin is an endopeptidase. Endopeptidases are enzymes that are responsible for breaking bonds between the individual amino acids, the peptide bonds. This allows proteins from food to be broken up into peptide fragments. These are then in turn broken down into the individual amino acids by other peptidases.

As an endopeptidase, chymotrypsin belongs to the group of serine proteases. This means that the amino acid serine is located in the so-called active center, i.e. the main work area of ​​the enzyme. This has a certain group (Hydroxyl group), which is important in breaking a peptide bond.

The proteins that chymotrypsin crushes are always split at certain positions in the sequence of amino acids. These are the so-called aromatic amino acids phenylalanine, tryptophan and tyrosine.

The splitting function of chymotrypsin also plays a role in medicine in the breakdown of immune complexes that could damage the body. In addition, chymotrypsin can relieve inflammation or pain in the musculoskeletal system. It reduces classic signs of inflammation, such as swelling or local reddening of the skin. Occasionally it is also used to loosen mucus in pneumonia or asthma.

What forms of chymotrypsin are there?

Chymotrypsin is, in effect, a family of different forms. They all have in common that they are serine proteases from the pancreas.

First of all, a distinction must be made between the inactive and the active form. In the pancreas, an inactive precursor (a so-called zymogen) made from chymotrypsin, which is called chymotrypsinogen. If this is released from the pancreas and reaches the small intestine, it can be broken down by trypsin, another enzyme from the pancreas, and converted into the active chymotrypsin. The chymptrypsinogen is broken down into three parts.

Furthermore, a distinction can be made between chymotrypsin A, B1, B2 and C. The most relevant forms for the human body are chymotrypsin B1 and chymotrypsin B2. The form chymotrypsin C was discovered in the pancreas of pigs that lack the B form.

You might also be interested in: Trypsin

How do the different forms differ?

The different forms of chymotrypsin are all serine proteases, in whose active center (this is where the main activity of the enzyme takes place) is the amino acid serine. The differences between the forms arise in the structure, the points at which the proteins are cleaved (cleavage or substrate specificity), and the activity.

The precursor chymotrypsinogen is inactive and not able to cleave proteins at their peptide bonds. The chymotrypsin itself, on the other hand, is active and able to function due to the cleavage by trypsin.

All forms split the proteins on the amino acids tyrosine and tryptophan. Chymotrypsin B also cleaves other bonds that are found in the glucagon molecule, for example.

Where is chymotrypsin made?

Chymotrypsin is formed in the pancreas, the so-called exocrine part of the pancreas. There, chymotrypsin is initially inactive in a preliminary stage (Zymogen) manufactured. This form of zymogen is also called chymotrypsinogen. If chymotrypsinogen reaches the small intestine, it is then split into three different parts by the pancreatic enzyme trypsin, whereby the active chymotrypsin is also formed.

You might also be interested in: Trypsin

At what pH value does chymotrypsin work best?

Since chymotrypsin can only work properly as a digestive enzyme at a certain pH value, it is important that the pH values ​​in the gastrointestinal section remain reasonably constant. Chymotrypsin is fully effective at a pH between 7 and 9, which is usually within the pH range of the entire small intestine.

How do you determine the chymotrypsin value?

A stool sample is required to determine the chymotrypsin level. In this, the activity of chymotrypsin is determined using so-called photometry. With the help of a special device that can measure certain wavelengths in the form of light absorption, the stool sample is checked to see whether and, if so, to what extent chymotrypsin is active. This measuring method is also used in medicine for numerous other measurements.

What are the normal values?

In a healthy person, the activity measurement of chymotrypsin is more than 6 U / g (units per gram of stool). If the value is between 3 and 6 U / g, this finding should be checked again as soon as possible. If the value is below 3 U / g, this is with great certainty an indication of a disease of the pancreas, which leads to a deficiency of chymotrypsin.

Also read: These are the symptoms of pancreatic disease!

Deficiency of chymotrypsin

What happens if there is a lack of chymotrypsin?

If there is a deficiency in chymotrypsin, the proteins from the food ingested can only be broken down insufficiently and important nutrients can no longer be absorbed in sufficient concentration. As a result, the entire mucous membrane of the intestine is disturbed and bacterial overgrowth, inflammation and regression of the surface occur (Atrophy of the small intestine villi). In addition, the lack of absorption leads to weight loss and deficiency symptoms, as important proteins from food can no longer be broken down and put into the circulation.

Causes of Deficiency

A deficiency in chymotrypsin can result from what is known as exocrine pancreatic insufficiency. This means that the part of the pancreas that is responsible for producing digestive enzymes, including chymotrypsin, is damaged. Exocrine pancreatic insufficiency, in turn, can have various causes, such as cystic fibrosis (Cystic fibrosis), inflammation of the pancreas (Pancreatitis), Gallstones, excessive alcohol abuse, or infections. Other possible causes can be tumors of the pancreas or various drugs.

If one of the diseases mentioned is suspected, however, other diagnostic measures should also be carried out for clarification.

For more information, see: Pancreatic insufficiency

What can you do with a deficiency?

If there is a lack of chymotrypsin, this can be compensated by giving enzyme preparations. These are enzyme supplements for the pancreas, that is, a tablet that contains several enzymes that are normally made in the pancreas. However, this should only be done in close consultation with a doctor, since in the case of a chymotrypsin deficiency, the cause of this deficiency, i.e. exocrine pancreatic insufficiency, must always be treated. The enzyme preparations must be taken with meals so that the ingested food can be broken down directly.

Read more about: Pancreatic insufficiency