Trypsin

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Trypsin
ChimeraX rendering of bovine trypsin (PDB 1UTN).png
Crystal structure of bovine trypsin. [1]
Identifiers
EC no. 3.4.21.4
CAS no. 9002-07-7
Databases
IntEnz IntEnz view
BRENDA BRENDA entry
ExPASy NiceZyme view
KEGG KEGG entry
MetaCyc metabolic pathway
PRIAM profile
PDB structures RCSB PDB PDBe PDBsum
Gene Ontology AmiGO / QuickGO
Search
PMC articles
PubMed articles
NCBI proteins
Trypsin
Identifiers
SymbolTrypsin
Pfam PF00089
InterPro IPR001254
SMART SM00020
PROSITE PDOC00124
MEROPS S1
SCOP2 1c2g / SCOPe / SUPFAM
CDD cd00190
Available protein structures:
Pfam   structures / ECOD  
PDB RCSB PDB; PDBe; PDBj
PDBsum structure summary

Trypsin is an enzyme in the first section of the small intestine that starts the digestion of protein molecules by cutting long chains of amino acids into smaller pieces. It is a serine protease from the PA clan superfamily, found in the digestive system of many vertebrates, where it hydrolyzes proteins. [2] [3] Trypsin is formed in the small intestine when its proenzyme form, the trypsinogen produced by the pancreas, is activated. Trypsin cuts peptide chains mainly at the carboxyl side of the amino acids lysine or arginine. It is used for numerous biotechnological processes. The process is commonly referred to as trypsinogen proteolysis or trypsinization, and proteins that have been digested/treated with trypsin are said to have been trypsinized. [4] Trypsin was discovered in 1876 by Wilhelm Kühne and was named from the Ancient Greek word for rubbing since it was first isolated by rubbing the pancreas with glycerin. [5]

Contents

Function

In the duodenum, trypsin catalyzes the hydrolysis of peptide bonds, breaking down proteins into smaller peptides. The peptide products are then further hydrolyzed into amino acids via other proteases, rendering them available for absorption into the blood stream. Tryptic digestion is a necessary step in protein absorption, as proteins are generally too large to be absorbed through the lining of the small intestine. [6]

Trypsin is produced as the inactive zymogen trypsinogen in the pancreas. When the pancreas is stimulated by cholecystokinin, it is then secreted into the first part of the small intestine (the duodenum) via the pancreatic duct. Once in the small intestine, the enzyme enterokinase (also called enteropeptidase) activates trypsinogen into trypsin by proteolytic cleavage. The trypsin then activates additional trypsin, chymotrypsin and carboxypeptidase.

Mechanism

The enzymatic mechanism is similar to that of other serine proteases. These enzymes contain a catalytic triad consisting of histidine-57, aspartate-102, and serine-195. [7] This catalytic triad was formerly called a charge relay system, implying the abstraction of protons from serine to histidine and from histidine to aspartate, but owing to evidence provided by NMR that the resultant alkoxide form of serine would have a much stronger pull on the proton than does the imidazole ring of histidine, current thinking holds instead that serine and histidine each have effectively equal share of the proton, forming short low-barrier hydrogen bonds therewith. [8] [ page needed ] By these means, the nucleophilicity of the active site serine is increased, facilitating its attack on the amide carbon during proteolysis. The enzymatic reaction that trypsin catalyzes is thermodynamically favorable, but requires significant activation energy (it is "kinetically unfavorable"). In addition, trypsin contains an "oxyanion hole" formed by the backbone amide hydrogen atoms of Gly-193 and Ser-195, which through hydrogen bonding stabilize the negative charge which accumulates on the amide oxygen after nucleophilic attack on the planar amide carbon by the serine oxygen causes that carbon to assume a tetrahedral geometry. Such stabilization of this tetrahedral intermediate helps to reduce the energy barrier of its formation and is concomitant with a lowering of the free energy of the transition state. Preferential binding of the transition state is a key feature of enzyme chemistry.

The negative aspartate residue (Asp 189) located in the catalytic pocket (S1) of trypsin is responsible for attracting and stabilizing positively charged lysine and/or arginine, and is, thus, responsible for the specificity of the enzyme. This means that trypsin predominantly cleaves proteins at the carboxyl side (or "C-terminal side") of the amino acids lysine and arginine except when either is bound to a C-terminal proline, [9] although large-scale mass spectrometry data suggest cleavage occurs even with proline. [10] Trypsin is considered an endopeptidase, i.e., the cleavage occurs within the polypeptide chain rather than at the terminal amino acids located at the ends of polypeptides.

Properties

Human trypsin has an optimal operating temperature of about 37 °C. [11] In contrast, the Atlantic cod has several types of trypsins for the poikilotherm fish to survive at different body temperatures. Cod trypsins include trypsin I with an activity range of 4 to 65 °C (40 to 150 °F) and maximal activity at 55 °C (130 °F), as well as trypsin Y with a range of 2 to 30 °C (36 to 86 °F) and a maximal activity at 21 °C (70 °F). [12]

As a protein, trypsin has various molecular weights depending on the source. For example, a molecular weight of 23.3 kDa is reported for trypsin from bovine and porcine sources.

The activity of trypsin is not affected by the enzyme inhibitor tosyl phenylalanyl chloromethyl ketone, TPCK, which deactivates chymotrypsin.

Trypsin should be stored at very cold temperatures (between −20 and −80 °C) to prevent autolysis, which may also be impeded by storage of trypsin at pH 3 or by using trypsin modified by reductive methylation. When the pH is adjusted back to pH 8, activity returns.

Isozymes

These human genes encode proteins with trypsin enzymatic activity:

protease, serine, 1 (trypsin 1)
Identifiers
Symbol PRSS1
Alt. symbolsTRY1
NCBI gene 5644
HGNC 9475
OMIM 276000
RefSeq NM_002769
UniProt P07477
Other data
EC number 3.4.21.4
Locus Chr. 7 q32-qter
Search for
Structures Swiss-model
Domains InterPro
protease, serine, 2 (trypsin 2)
Identifiers
Symbol PRSS2
Alt. symbolsTRYP2
NCBI gene 5645
HGNC 9483
OMIM 601564
RefSeq NM_002770
UniProt P07478
Other data
EC number 3.4.21.4
Locus Chr. 7 q35
Search for
Structures Swiss-model
Domains InterPro
protease, serine, 3 (mesotrypsin)
Identifiers
Symbol PRSS3
Alt. symbolsPRSS4
NCBI gene 5646
HGNC 9486
OMIM 613578
RefSeq NM_002771
UniProt P35030
Other data
EC number 3.4.21.4
Locus Chr. 9 p13
Search for
Structures Swiss-model
Domains InterPro

Other isoforms of trypsin may also be found in other organisms.

Clinical significance

Activation of trypsin from proteolytic cleavage of trypsinogen in the pancreas can lead to a series of events that cause pancreatic self-digestion, resulting in pancreatitis. One consequence of the autosomal recessive disease cystic fibrosis is a deficiency in transport of trypsin and other digestive enzymes from the pancreas. This leads to the disorder termed meconium ileus, which involves intestinal obstruction (ileus) due to overly thick meconium, which is normally broken down by trypsin and other proteases, then passed in feces. [13]

Applications

Trypsin is available in high quantity in pancreases, and can be purified rather easily. Hence, it has been used widely in various biotechnological processes.

In a tissue culture lab, trypsin is used to resuspend cells adherent to the cell culture dish wall during the process of harvesting cells. [14] Some cell types adhere to the sides and bottom of a dish when cultivated in vitro . Trypsin is used to cleave proteins holding the cultured cells to the dish, so that the cells can be removed from the plates.

Trypsin can also be used to dissociate dissected cells (for example, prior to cell fixing and sorting).

Trypsin can be used to break down casein in breast milk. If trypsin is added to a solution of milk powder, the breakdown of casein causes the milk to become translucent. The rate of reaction can be measured by using the amount of time needed for the milk to turn translucent.

Trypsin is commonly used in biological research during proteomics experiments to digest proteins into peptides for mass spectrometry analysis, e.g. in-gel digestion. Trypsin is particularly suited for this, since it has a very well defined specificity, as it hydrolyzes only the peptide bonds in which the carbonyl group is contributed either by an arginine or lysine residue.

Trypsin can also be used to dissolve blood clots in its microbial form and treat inflammation in its pancreatic form.

In veterinary medicine, trypsin is an ingredient in wound spray products, such as Debrisol, to dissolve dead tissue and pus in wounds in horses, cattle, dogs, and cats. [15]

In food

Commercial protease preparations usually consist of a mixture of various protease enzymes that often includes trypsin. These preparations are widely used in food processing: [16]

Trypsin inhibitor

To prevent the action of active trypsin in the pancreas, which can be highly damaging, inhibitors such as BPTI and SPINK1 in the pancreas and α1-antitrypsin in the serum are present as part of the defense against its inappropriate activation. Any trypsin prematurely formed from the inactive trypsinogen is then bound by the inhibitor. The protein-protein interaction between trypsin and its inhibitors is one of the tightest bound, and trypsin is bound by some of its pancreatic inhibitors nearly irreversibly. [17] In contrast with nearly all known protein assemblies, some complexes of trypsin bound by its inhibitors do not readily dissociate after treatment with 8M urea. [18]

Trypsin inhibitors can serve as tools when addressing metabolic and obesity disorders. Metabolic disorders, obesity, and being overweight are known to increase non-communicable chronic disease prevalence. [19] It is of public health policy interest to explore various ways to mitigate this occurrence including use of trypsin inhibitors. These inhibitors have capabilities of reducing colon, breast, skin, nad prostate cancer by way of radioprotective and anticarcinogenic activity. Trypsin inhibitors can act as regulatory mechanisms to control release of neutrophil proteases and avoid significant tissue damage. [19] In regards to cardiovascular conditions associated with unproductive serine protease activity, trypsin inhibitors can block their activity in platelet aggregation, fibrinolysis, coagulation, and blood coagulation.

The multifunctionality of trypsin inhibitors includes being potential protease inhibitors for AMP activity. [20] While the antibacterial action mechanisms of trypsin inhibitors are unclear, studies have aimed to study their mechanisms as potential applications in bacterial infection treatments. [20] Research and scanning microscopy showed antibacterial effects on bacterial membranes from Staphylococcus aureus. [20] Trypsin inhibitors from amphibian skin showed bacterial death promotion that affected Staphylococcus aureus' cell wall and membrane. [20] Studies also analyzed antibacterial actions in trypsin inhibitor peptides, proteins, and E. coli. The results showed sufficient bacterial growth prevention. However, trypsin inhibitors have to meet certain criteria to be utilized in foods and medical treatments. [20]

Trypsin alternatives

Trypsin digestion of extra cellular matrix is a common practice in cell culture. However this enzymatic degradation of the cells can negatively effect cell viability and surface markers, especially in stem cells. There are gentler alternatives than trypsin such as Accutase which doesn't effect surface markers such as cd14, cd117, cd49f, cd292. [21] [22] However Accutase decreases the surface levels of FasL and Fas receptor on macrophages, these receptors are associated with cell cytotoxicity in the immune system and can also facilitate apoptosis-related cell death. [23]

ProAlanase could also serve as an alternative to Trypsin in proteomic applications. [24] ProAlanase is an Aspergillus niger fungus protease that can achieve high proteolytic activity and specificity for digestion under the correct conditions. [24] ProAnalase, the acidic prolyl-endopeptidase protease, previously studied as An-PEP, has been observed in various experiments to define its specificity. [24] ProAnalase performed optimally in LC-MS applications with short digestion times and highly acidic pH. [24]

See also

Related Research Articles

<span class="mw-page-title-main">Chymotrypsin</span> Digestive enzyme

Chymotrypsin (EC 3.4.21.1, 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 duodenum, where it performs proteolysis, the breakdown of proteins and polypeptides. Chymotrypsin preferentially cleaves peptide amide bonds where the side chain of the amino acid N-terminal to the scissile amide bond (the P1 position) is a large hydrophobic amino acid (tyrosine, tryptophan, and phenylalanine). These amino acids contain an aromatic ring in their side chain that fits into a hydrophobic pocket (the S1 position) of the enzyme. It is activated in the presence of trypsin. The hydrophobic and shape complementarity between the peptide substrate P1 side chain and the enzyme S1 binding cavity accounts for the substrate specificity of this enzyme. Chymotrypsin also hydrolyzes other amide bonds in peptides at slower rates, particularly those containing leucine at the P1 position.

<span class="mw-page-title-main">Proteolysis</span> Breakdown of proteins into smaller polypeptides or amino acids

Proteolysis is the breakdown of proteins into smaller polypeptides or amino acids. Uncatalysed, the hydrolysis of peptide bonds is extremely slow, taking hundreds of years. Proteolysis is typically catalysed by cellular enzymes called proteases, but may also occur by intra-molecular digestion.

<span class="mw-page-title-main">Protease</span> Enzyme that cleaves other proteins into smaller peptides

A protease is an enzyme that catalyzes proteolysis, breaking down proteins into smaller polypeptides or single amino acids, and spurring the formation of new protein products. They do this by cleaving the peptide bonds within proteins by hydrolysis, a reaction where water breaks bonds. Proteases are involved in numerous biological pathways, including digestion of ingested proteins, protein catabolism, and cell signaling.

Digestion is the breakdown of large insoluble food compounds into small water-soluble components so that they can be absorbed into the blood plasma. In certain organisms, these smaller substances are absorbed through the small intestine into the blood stream. Digestion is a form of catabolism that is often divided into two processes based on how food is broken down: mechanical and chemical digestion. The term mechanical digestion refers to the physical breakdown of large pieces of food into smaller pieces which can subsequently be accessed by digestive enzymes. Mechanical digestion takes place in the mouth through mastication and in the small intestine through segmentation contractions. In chemical digestion, enzymes break down food into the small compounds that the body can use.

<span class="mw-page-title-main">Serine protease</span> Class of enzymes

Serine proteases are enzymes that cleave peptide bonds in proteins. Serine serves as the nucleophilic amino acid at the (enzyme's) active site. They are found ubiquitously in both eukaryotes and prokaryotes. Serine proteases fall into two broad categories based on their structure: chymotrypsin-like (trypsin-like) or subtilisin-like.

<span class="mw-page-title-main">Metalloproteinase</span> Type of enzyme

A metalloproteinase, or metalloprotease, is any protease enzyme whose catalytic mechanism involves a metal. An example is ADAM12 which plays a significant role in the fusion of muscle cells during embryo development, in a process known as myogenesis.

<span class="mw-page-title-main">Digestive enzyme</span> Class of enzymes

Digestive enzymes are a group of enzymes that break down polymeric macromolecules into their smaller building blocks, in order to facilitate their absorption into the cells of the body. Digestive enzymes are found in the digestive tracts of animals and in the tracts of carnivorous plants, where they aid in the digestion of food, as well as inside cells, especially in their lysosomes, where they function to maintain cellular survival. Digestive enzymes of diverse specificities are found in the saliva secreted by the salivary glands, in the secretions of cells lining the stomach, in the pancreatic juice secreted by pancreatic exocrine cells, and in the secretions of cells lining the small and large intestines.

Trypsinogen is the precursor form 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 enteropeptidase, which is found in the intestinal mucosa. Once activated, the trypsin can cleave more trypsinogen into trypsin, a process called autoactivation. Trypsin cleaves the peptide bond on the carboxyl side of basic amino acids such as arginine and lysine.

<span class="mw-page-title-main">Enteropeptidase</span> Class of enzymes

Enteropeptidase is an enzyme produced by cells of the duodenum and is involved in digestion in humans and other animals. Enteropeptidase converts trypsinogen into its active form trypsin, resulting in the subsequent activation of pancreatic digestive enzymes. Absence of enteropeptidase results in intestinal digestion impairment.

<span class="mw-page-title-main">Catalytic triad</span> Set of three coordinated amino acids

A catalytic triad is a set of three coordinated amino acids that can be found in the active site of some enzymes. Catalytic triads are most commonly found in hydrolase and transferase enzymes. An acid-base-nucleophile triad is a common motif for generating a nucleophilic residue for covalent catalysis. The residues form a charge-relay network to polarise and activate the nucleophile, which attacks the substrate, forming a covalent intermediate which is then hydrolysed to release the product and regenerate free enzyme. The nucleophile is most commonly a serine or cysteine amino acid, but occasionally threonine or even selenocysteine. The 3D structure of the enzyme brings together the triad residues in a precise orientation, even though they may be far apart in the sequence.

<span class="mw-page-title-main">Cysteine protease</span> Class of enzymes

Cysteine proteases, also known as thiol proteases, are hydrolase enzymes that degrade proteins. These proteases share a common catalytic mechanism that involves a nucleophilic cysteine thiol in a catalytic triad or dyad.

A trypsin inhibitor (TI) is a protein and a type of serine protease inhibitor (serpin) that reduces the biological activity of trypsin by controlling the activation and catalytic reactions of proteins. Trypsin is an enzyme involved in the breakdown of many different proteins, primarily as part of digestion in humans and other animals such as monogastrics and young ruminants. Serpins – including trypsin inhibitors – are irreversible and suicide substrate-like inhibitors.

<span class="mw-page-title-main">Aminopeptidase</span> Class of enzymes

Aminopeptidases are enzymes that catalyze the cleavage of amino acids from the amino terminus (N-terminus) of proteins or peptides (exopeptidases). "They are widely distributed throughout the animal and plant kingdoms and are found in many subcellular organelles, in cytosol, and as membrane components. Aminopeptidases are used in essential cellular functions. Many, but not all, of these peptidases are zinc metalloenzymes."

Protein metabolism denotes the various biochemical processes responsible for the synthesis of proteins and amino acids (anabolism), and the breakdown of proteins by catabolism.

Serine hydrolases are one of the largest known enzyme classes comprising approximately ~200 enzymes or 1% of the genes in the human proteome. A defining characteristic of these enzymes is the presence of a particular serine at the active site, which is used for the hydrolysis of substrates. The hydrolysis of the ester or peptide bond proceeds in two steps. First, the acyl part of the substrate is transferred to the serine, making a new ester or amide bond and releasing the other part of the substrate is released. Later, in a slower step, the bond between the serine and the acyl group is hydrolyzed by water or hydroxide ion, regenerating free enzyme. Unlike other, non-catalytic, serines, the reactive serine of these hydrolases is typically activated by a proton relay involving a catalytic triad consisting of the serine, an acidic residue and a basic residue, although variations on this mechanism exist.

<span class="mw-page-title-main">Trypsin 1</span> Protein-coding gene in the species Homo sapiens

Trypsin-1, also known as cationic trypsinogen, is a protein that in humans is encoded by the PRSS1 gene. Trypsin-1 is the main isoform of trypsinogen secreted by pancreas, the others are trypsin-2, and trypsin-3 (meso-trypsinogen).

<span class="mw-page-title-main">SPINK1</span> Protein-coding gene in the species Homo sapiens

Pancreatic secretory trypsin inhibitor (PSTI) also known as serine protease inhibitor Kazal-type 1 (SPINK1) or tumor-associated trypsin inhibitor (TATI) is a protein that in humans is encoded by the SPINK1 gene.

<span class="mw-page-title-main">KLK6</span> Protein-coding gene in the species Homo sapiens

Kallikrein-6 is a protein that in humans is encoded by the KLK6 gene. Kallikrein-6 is also referred to as neurosin, protease M, hK6, or zyme. It is a 223 amino acid sequence, derived from its 244 original form, which contains a 16 residue presignal and 5 residue activation peptide.

<span class="mw-page-title-main">Kunitz STI protease inhibitor</span>

Kunitz soybean trypsin inhibitor is a type of protein contained in legume seeds which functions as a protease inhibitor. Kunitz-type Soybean Trypsin Inhibitors are usually specific for either trypsin or chymotrypsin. They are thought to protect seeds against consumption by animal predators.

<span class="mw-page-title-main">PRSS3</span> Protein-coding gene in the species Homo sapiens

Protease, serine, 3 is a protein that in humans is encoded by the PRSS3 gene.

References

  1. ↑ PDB: 1UTN ​; Leiros HK, Brandsdal BO, Andersen OA, Os V, Leiros I, Helland R, et al. (April 2004). "Trypsin specificity as elucidated by LIE calculations, X-ray structures, and association constant measurements". Protein Science. 13 (4): 1056–70. doi: 10.1110/ps.03498604 . PMC   2280040 . PMID   15044735.
  2. ↑ Rawlings ND, Barrett AJ (1994). "[2] Families of serine peptidases" . Families of serine peptidases. Methods in Enzymology. Vol. 244. pp. 19–61. doi:10.1016/0076-6879(94)44004-2. ISBN   978-0-12-182145-6. PMC   7133253 . PMID   7845208.
  3. ↑ The German physiologist Wilhelm Kühne (1837-1900) discovered trypsin in 1876. See: Kühne W (1877). "Über das Trypsin (Enzym des Pankreas)". Verhandlungen des Naturhistorisch-medicinischen Vereins zu Heidelberg. new series. 1 (3): 194–198 – via Google Books. Open Access logo PLoS transparent.svg
  4. ↑ Engelking LR (2015-01-01). "Chapter 7 - Protein Digestion". Textbook of Veterinary Physiological Chemistry (Third ed.). Boston: Academic Press. pp. 39–44. doi:10.1016/B978-0-12-391909-0.50007-4. ISBN   978-0-12-391909-0.
  5. ↑ Kühne W (March 6, 1876). "Ueber das Trypsin (Enzym des Pankreas)" [About trypsin (enzyme of the pancreas)]. In Naturhistorisch-medizinischen Verein (ed.). Verhandlungen des Naturhistorisch-medizinischen Vereins zu Heidelberg[Negotiations by the Natural History Medical Association in Heidelberg] (in German). Heidelberg, Germany: Carl Winter's Universitätsbuchhandlung (published 1877). pp. 194–8 – via Archive.org.
  6. ↑ "Digestion of Proteins". Elective course (Clinical biochemistry). Ternopil National Medical University. July 14, 2015. Archived from the original on August 8, 2020. Retrieved April 11, 2020.
  7. ↑ Polgár L (October 2005). "The catalytic triad of serine peptidases". Cellular and Molecular Life Sciences. 62 (19–20): 2161–72. doi:10.1007/s00018-005-5160-x. PMID   16003488. S2CID   3343824.
  8. ↑ Voet D, Voet JG (2011). Biochemistry (4th ed.). Hoboken, NJ: John Wiley & Sons. ISBN   978-0-470-57095-1. OCLC   690489261.
  9. ↑ "Sequencing Grade Modified Trypsin" (PDF). promega.com. 2007-04-01. Archived from the original (PDF) on 2003-05-19. Retrieved 2009-02-08.
  10. ↑ Rodriguez J, Gupta N, Smith RD, Pevzner PA (January 2008). "Does trypsin cut before proline?" (PDF). Journal of Proteome Research. 7 (1): 300–5. CiteSeerX   10.1.1.163.4052 . doi:10.1021/pr0705035. PMID   18067249. Archived from the original (PDF) on 2020-08-13. Retrieved 2017-10-25.
  11. ↑ Chelulei Cheison S, Brand J, Leeb E, Kulozik U (March 2011). "Analysis of the effect of temperature changes combined with different alkaline pH on the β-lactoglobulin trypsin hydrolysis pattern using MALDI-TOF-MS/MS". Journal of Agricultural and Food Chemistry. 59 (5): 1572–81. doi:10.1021/jf1039876. PMID   21319805.
  12. ↑ Gudmundsdóttir A, Pálsdóttir HM (2005). "Atlantic cod trypsins: from basic research to practical applications". Marine Biotechnology. 7 (2): 77–88. Bibcode:2005MarBt...7...77G. doi:10.1007/s10126-004-0061-9. PMID   15759084. S2CID   42480996.
  13. ↑ Noone PG, Zhou Z, Silverman LM, Jowell PS, Knowles MR, Cohn JA (December 2001). "Cystic fibrosis gene mutations and pancreatitis risk: relation to epithelial ion transport and trypsin inhibitor gene mutations". Gastroenterology. 121 (6): 1310–9. doi: 10.1053/gast.2001.29673 . PMID   11729110.
  14. ↑ "Trypsin-EDTA (0.25%)". Stem Cell Technologies. Retrieved 2012-02-23.
  15. ↑ "Debrisol". drugs.com.
  16. ↑ "Protease - GMO Database". GMO Compass. European Union. 2010-07-10. Archived from the original on 2015-02-24. Retrieved 2012-01-01.
  17. ↑ Voet D, Voet JG (1995). Biochemistry (2nd ed.). John Wiley & Sons. pp.  396–400. ISBN   978-0-471-58651-7.
  18. ↑ Levilliers N, Péron M, Arrio B, Pudles J (October 1970). "On the mechanism of action of proteolytic inhibitors. IV. Effect of 8 M urea on the stability of trypsin in trypsin-inhibitor complexes". Archives of Biochemistry and Biophysics. 140 (2): 474–83. doi:10.1016/0003-9861(70)90091-3. PMID   5528741.
  19. 1 2 Cristina Oliveira de Lima V, Piuvezam G, Leal Lima Maciel B, Heloneida de Araújo Morais A (December 2019). "Trypsin inhibitors: promising candidate satietogenic proteins as complementary treatment for obesity and metabolic disorders?". Journal of Enzyme Inhibition and Medicinal Chemistry. 34 (1): 405–419. doi:10.1080/14756366.2018.1542387. PMC   6327991 . PMID   30734596.
  20. 1 2 3 4 5 de Souza Nascimento AM, de Oliveira Segundo VH, Felipe Camelo Aguiar AJ, Piuvezam G, Souza Passos T, Florentino da Silva Chaves Damasceno KS, et al. (December 2022). "Antibacterial action mechanisms and mode of trypsin inhibitors: a systematic review". Journal of Enzyme Inhibition and Medicinal Chemistry. 37 (1): 749–759. doi:10.1080/14756366.2022.2039918. PMC   8856033 . PMID   35168466.
  21. ↑ Quan Y, Yan Y, Wang X, Fu Q, Wang W, Wu J, et al. (2012). "Impact of cell dissociation on identification of breast cancer stem cells". Cancer Biomarkers. 12 (3): 125–33. doi:10.3233/CBM-130300. PMID   23481571.
  22. ↑ Skog M, Sivlér P, Steinvall I, Aili D, Sjöberg F, Elmasry M (May 2019). "The Effect of Enzymatic Digestion on Cultured Epithelial Autografts". Cell Transplantation. 28 (5): 638–644. doi:10.1177/0963689719833305. PMC   7103596 . PMID   30983404.
  23. ↑ Lai TY, Cao J, Ou-Yang P, Tsai CY, Lin CW, Chen CC, et al. (April 2022). "Different methods of detaching adherent cells and their effects on the cell surface expression of Fas receptor and Fas ligand". Scientific Reports. 12 (1): 5713. Bibcode:2022NatSR..12.5713L. doi:10.1038/s41598-022-09605-y. PMC   8983651 . PMID   35383242.
  24. 1 2 3 4 Samodova D, Hosfield CM, Cramer CN, Giuli MV, Cappellini E, Franciosa G, et al. (December 2020). "ProAlanase is an Effective Alternative to Trypsin for Proteomics Applications and Disulfide Bond Mapping". Molecular & Cellular Proteomics. 19 (12): 2139–2157. doi: 10.1074/mcp.tir120.002129 . PMC   7710147 . PMID   33020190.

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