A trypsin inhibitor (TI) is a protein and a type of serine protease inhibitor (

serpin Serpins are a superfamily of proteins with similar structures that were first identified for their protease inhibition activity and are found in all kingdoms of life. The acronym serpin was originally coined because the first serpins to be id ...

) that reduces the

biological activity In pharmacology, biological activity or pharmacological activity describes the beneficial or adverse effects of a drug on living matter. When a drug is a complex chemical mixture, this activity is exerted by the substance's active ingredient or ...

trypsin Trypsin is an enzyme in the first section of the small intestine that starts the digestion of protein molecules by cutting these long chains of amino acids into smaller pieces. It is a serine protease from the PA clan superfamily, found in the d ...

by controlling the activation and catalytic reactions of proteins. Trypsin is an

enzyme Enzymes () are proteins that act as biological catalysts by accelerating chemical reactions. The molecules upon which enzymes may act are called substrates, and the enzyme converts the substrates into different molecules known as products ...

involved in the breakdown of many different

protein Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, res ...

s, primarily as part of

digestion Digestion is the breakdown of large insoluble food molecules into small water-soluble food molecules so that they can be absorbed into the watery blood plasma. In certain organisms, these smaller substances are absorbed through the small intest ...

in humans and other animals such as monogastrics and young

ruminant Ruminants (suborder Ruminantia) are hoofed herbivorous grazing or browsing mammals that are able to acquire nutrients from plant-based food by fermenting it in a specialized stomach prior to digestion, principally through microbial actions. The ...

s. Serpins – including trypsin inhibitors – are irreversible and suicide substrate-like inhibitors. It destructively alters trypsin thereby rendering it unavailable to bind with proteins for the digestion process. NIHMSID 336639. As a result, protease inhibitors that interfere with digestion activity have an

antinutrition Antinutrients are natural or synthetic compounds that interfere with the absorption of nutrients. Nutrition studies focus on antinutrients commonly found in food sources and beverages. Antinutrients may take the form of drugs, chemicals that natura ...

al effect. Therefore, trypsin inhibitors are considered an anti-nutritional factor or ANF. Additionally, trypsin inhibitor partially interferes with

chymotrypsin Chymotrypsin (, chymotrypsins A and B, alpha-chymar ophth, avazyme, chymar, chymotest, enzeon, quimar, quimotrase, alpha-chymar, alpha-chymotrypsin A, alpha-chymotrypsin) is a digestive enzyme component of pancreatic juice acting in the duod ...

function.

Trypsinogen Trypsinogen () is the precursor form (or zymogen) of trypsin, a digestive enzyme. It is produced by the pancreas and found in pancreatic juice, along with amylase, lipase, and chymotrypsinogen. It is cleaved to its active form, trypsin, by ent ...

is an inactive form of trypsin, its inactive form ensures protein aspects of the body, such as the pancreas and muscles, are not broken down. It is formed in the pancreas and activated to trypsin with enteropeptidase

Chymotrypsinogen Chymotrypsinogen is an inactive precursor (zymogen) of chymotrypsin, a digestive enzyme which breaks proteins down into smaller peptides. Chymotrypsinogen is a single polypeptide chain consisting of 245 amino acid residues. It is synthesized in th ...

is the inactive form of chymotrypsin and has similar functions as trypsin. The presence of trypsin inhibitor has been found to result in delayed growth as well as metabolic and digestive diseases. Additionally, pancreatic hypertrophy is a common occurrence with trypsin inhibitor consumption The presence of trypsin inhibitor in a product reduces the protein efficiency and therefore results in the consumers body not being able to efficiently and fully utilize the protein.

Function

Trypsin inhibitor is present in various foods such as soybeans, grains, cereals and various additional legumes. The main function of trypsin inhibitors in these foods is to act as a defense mechanism. By having this harmful component wild animals learn that any food that contains trypsin inhibitor is a food to avoid. Trypsin inhibitor can also be essential for biological processes within the plant. Trypsin inhibitor can also naturally occur in the pancreas of species such as bovines. The function of this is to protect the animal from any accidental activation of trypsinogen and/or chymotrypsinogen

Inactivation

Trypsin inhibitor is heat labile, therefore by exposing these foods to heat, the trypsin inhibitor is removed and the food subsequently becomes safe to eat. Boiling soybeans for 14 minutes inactivates about 80% of the inhibitor, and for 30 minutes, about 90%. At higher temperatures, e.g. in

pressure cookers Pressure cooking is the process of cooking food under high pressure steam and water or a water-based cooking liquid, in a sealed vessel known as a ''pressure cooker''. High pressure limits boiling, and creates higher cooking temperatures which c ...

, shorter cooking times are needed.

ELISA The enzyme-linked immunosorbent assay (ELISA) (, ) is a commonly used analytical biochemistry assay, first described by Eva Engvall and Peter Perlmann in 1971. The assay uses a solid-phase type of enzyme immunoassay (EIA) to detect the presen ...

tests can be used to measure the degree of deactivation achieved.

Applications in commercial industries

The most prominent application of trypsin inhibitor is livestock feed. Soybeans are a popular ingredient in livestock feed therefore trypsin inhibitor can be a concern due to the presence of it in soybeans. The majority of soybeans used in livestock feed is converted to soybean meal and through the process the trypsin inhibitor is removed due to the heat treatment. However, experiments have been done concerning animals who consume active trypsin inhibitor and they consistently have decreased weights. A study revealing that a protease inhibitor from the eggs of the

freshwater snail Freshwater snails are gastropod mollusks which live in fresh water. There are many different families. They are found throughout the world in various habitats, ranging from ephemeral pools to the largest lakes, and from small seeps and springs ...

Pomacea canaliculata ''Pomacea canaliculata'', commonly known as the golden apple snail or the channeled apple snail, is a species of large freshwater snail with gills and an operculum, an aquatic gastropod mollusc in the family Ampullariidae, the apple snail ...

'', interacting as a trypsin inhibitor with the protease of potential predators, was reported in 2010, the first direct evidence for this mechanism in the animal kingdom.

Clinical significance

The peptide tumor-associated trypsin inhibitor (TATI) has been used as a marker of mucinous ovarian carcinoma, urothelial carcinoma, and renal cell carcinoma. TATI is metabolised by the kidneys and is, thus, elevated in patients with

kidney failure Kidney failure, also known as end-stage kidney disease, is a medical condition in which the kidneys can no longer adequately filter waste products from the blood, functioning at less than 15% of normal levels. Kidney failure is classified as eit ...

. It may be elevated in non-neoplastic processes such as pancreatitis and can be used as a prognostic marker in this setting (levels above 70 micrograms/L are associated with poor prognosis). Fifty percent of stage I mucinous ovarian carcinomas are associated with elevated TATI, and nearly 100% of stage IV tumors show elevated TATI. Eighty-five to 95% of pancreatic adenocarcinomas are associated with increased TATI (but elevation in pancreatitis limits the clinical utility of TATI in this setting; see above). Sixty percent of gastric adenocarcinomas show elevated TATI, in particular tumors of diffusely infiltrative/signet ring type. TATI, thus, complements CEA, which is elevated exclusively in intestinal type adenocarcinoma of the stomach. In urothelial carcinoma, TATI expression varies with stage, ranging from 20% in low-stage tumors to 80% of high-stage tumors. TATI sensitivity in the setting of renal cell carcinoma is approximately 70%. Elevated TATI is more likely to be seen in patients with advanced-stage disease. In nearly all tumor types studied, TATI is a marker of poor prognosis.De Mais, Daniel. ASCP Quick Compendium of Clinical Pathology, 2nd Ed. ASCP Press 2009.

References

* Jones et al., Biochem., 2, 66, (1963) * Lineweaver and Murray JBC, 171, 565 (1947) * Kunitz and Northrop J. Gen. Physiol., 19, 991 (1936) * Fraenkel-Conrat, et al., Arch. Biochem. Biophys., 37, 393 (1952) * Frattali, V., and Steiner, R.: Biochem., 7, 521 (1968)

External links

* {{DEFAULTSORT:Trypsin Inhibitor EC 3.4.21 Hydrolase inhibitors