Trypsin

2017-11-29T15:19:28Z

2405:204:528E:3024:0:0:28BA:40AC:

{{enzyme
| Name = Trypsin
| EC_number = 3.4.21.4
| CAS_number = 9002-07-7
| IUBMB_EC_number = 3/4/21/4
| GO_code = 0004295
| image =
| width =
| caption =
}}
{{Pfam box
| Symbol = Trypsin
| Name = Trypsin
| image = 1UTN.png
| width =
| caption = [[X-ray crystallography#Biological macromolecular crystallography|Crystal structure]] of [[cattle|bovine]] trypsin.<ref name="pmid15044735">{{PDB|1UTN}}; {{cite journal |vauthors=Leiros HK, Brandsdal BO, Andersen OA, Os V, Leiros I, Helland R, Otlewski J, Willassen NP, Smalås AO | title = Trypsin specificity as elucidated by LIE calculations, X-ray structures, and association constant measurements | journal = Protein Sci. | volume = 13 | issue = 4 | pages = 1056–70 |date=April 2004 | pmid = 15044735 | pmc = 2280040 | doi = 10.1110/ps.03498604 | url = }}</ref>
| Pfam = PF00089
| InterPro = IPR001254
| SMART = SM00020
| PROSITE = PDOC00124
| MEROPS = S1
| SCOP = 1c2g
| TCDB =
| CDD = cd00190
| OPM family =
| OPM protein =
}}
'''Trypsin''' ({{EC number|3.4.21.4}}) is a [[serine protease]] from the [[PA clan]] superfamily, found in the [[digestive system]] of many [[vertebrates]], where it [[hydrolysis|hydrolyses]] [[protein]]s.<ref name="pmid7845208">{{cite journal |vauthors=Rawlings ND, Barrett AJ | title = Families of serine peptidases | journal = Methods Enzymol. | volume = 244 | issue = | pages = 19–61 | year = 1994 | pmid = 7845208 | doi = 10.1016/0076-6879(94)44004-2| url = | series = Methods in Enzymology | isbn = 978-0-12-182145-6 }}</ref><ref>The German physiologist [[Wilhelm Kühne]] (1837-1900) discovered trypsin in 1876. See: W. Kühne (1877) "[https://books.google.com/books?id=jzdMAAAAYAAJ&pg=PA194&ie=ISO-8859-1&output=html Über das Trypsin (Enzym des Pankreas)]", ''Verhandlungen des naturhistorisch-medicinischen Vereins zu Heidelberg'', new series, vol. 1, no. 3, pages 194-198.</ref> Trypsin is formed in the [[small intestine]] when its [[zymogen|proenzyme]] form, the [[trypsinogen]] produced by the [[pancreas]], is activated. Trypsin cleaves [[peptide]] chains mainly at the [[carboxyl]] side of the [[amino acids]] [[lysine]] or [[arginine]], except when either is followed by [[proline]].<ref>{{Cite book|url=https://books.google.com/books?id=_xDMAwAAQBAJ&printsec=frontcover&hl=tr&source=gbs_ge_summary_r&cad=0#v=twopage&q&f=false|title=Textbook of Veterinary Physiological Chemistry: Veterinary medicine, Veterinary medicine|last=Reviews|first=C. T. I.|date=2016-09-26|publisher=Cram101 Textbook Reviews|isbn=9781490289472|language=en}}{{tertiary source}}</ref> It is used for numerous [[biotechnological]] processes. The process is commonly referred to as trypsin [[proteolysis]] or [[trypsinisation]], and proteins that have been digested/treated with trypsin are said to have been trypsinized.<ref>{{Cite book|url=http://www.sciencedirect.com/science/article/pii/B9780123919090500074|title=Textbook of Veterinary Physiological Chemistry (Third Edition)|last=Engelking|first=Larry R.|date=2015-01-01|publisher=Academic Press|isbn=9780123919090|location=Boston|pages=39–44}}</ref> Trypsin was discovered in 1876 by Wilhelm Kühne.<ref>{{Cite web|url=https://archive.org/stream/verhandlungendes7477natu#page/190/mode/2up|title=Verhandlungen des Naturhistorisch-medizinischen Vereins zu Heidelberg|website=archive.org|access-date=2017-04-24}}</ref>

== Function ==

In the [[duodenum]], trypsin [[catalysis|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]].<ref>{{Cite web|url=http://intranet.tdmu.edu.ua/data/kafedra/internal/distance/lectures_stud/English/2%20course/Elective%20course%20(Clinical%20biochemistry)/10.%20METABOLISM%20OF%20AMINOACIDS.%20DIGESTION%20OF%20%20PROTEINS..htm|title=DIGESTION OF PROTEINS|website=intranet.tdmu.edu.ua|access-date=2017-04-24}}</ref>

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 [[enteropeptidase]] activates trypsinogen into trypsin by [[proteolytic cleavage]]. Auto catalysis does not happen with trypsin, as trypsinogen is a poor substrate, therefore enzymatic damage to the pancreas is avoided. <ref>{{Cite web|url=http://intranet.tdmu.edu.ua/data/kafedra/internal/distance/lectures_stud/English/2%20course/Elective%20course%20(Clinical%20biochemistry)/10.%20METABOLISM%20OF%20AMINOACIDS.%20DIGESTION%20OF%20%20PROTEINS..htm|title=DIGESTION OF PROTEINS|website=intranet.tdmu.edu.ua|access-date=2017-04-24}}</ref>

== 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.<ref name="pmid16003488">{{cite journal | author = Polgár L | title = The catalytic triad of serine peptidases | journal = Cell. Mol. Life Sci. | volume = 62 | issue = 19–20 | pages = 2161–72 |date=October 2005 | pmid = 16003488 | doi = 10.1007/s00018-005-5160-x | url = }}</ref> These three residues form a charge relay that increases [[nucleophile|nucleophilicity]] of the [[active site]] serine. This is achieved by modifying the electrostatic environment of the serine. The enzymatic reaction that trypsin catalyzes is [[thermodynamics|thermodynamically]] favorable but requires significant [[activation energy]] (it is "[[enzyme kinetics|kinetically]] unfavorable"). In addition, trypsin contains an "oxyanion hole" formed by the backbone amide hydrogen atoms of Gly-193 and Ser-195, which serves to stabilize the developing negative charge on the carbonyl oxygen atom of the cleaved amides.

The 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 [[protein]]s at the [[carboxyl]] side (or "[[C-terminal]] side") of the [[amino acid]]s [[lysine]] and arginine except when either is bound to a C-terminal [[proline]],<ref name="urlwww.promega.com">{{cite web | url = http://www.promega.com/tbs/9piv511/9piv511.pdf | title =Sequencing Grade Modified Trypsin | date = 2007-04-01 | format = | work = | publisher = www.promega.com | pages = | language = | archiveurl = | archivedate = | quote = | accessdate = 2009-02-08}}</ref> although large-scale mass spectrometry data suggest cleavage occurs even with proline.<ref name="pmid18067249">{{cite journal |vauthors=Rodriguez J, Gupta N, Smith RD, Pevzner PA | title = Does trypsin cut before proline? | journal = J. Proteome Res. | volume = 7 | issue = 1 | pages = 300–305 | year = 2008 | pmid = 18067249 | doi=10.1021/pr0705035| url = http://proteomics.ucsd.edu/pavel/papers/does_trypsin_cut_before_proline.pdf }}</ref> 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 [[peptide|polypeptides]].

== Properties ==
Human trypsin has an optimal [[operating temperature]] of about 37 °C.<ref>{{cite web|url=http://cdn.intechopen.com/pdfs-wm/29629.pdf|title=A Critical Review of Trypsin Digestion for LC-MS Based Proteomics|author1=Hanne Kolsrud Hustoft |author2=Helle Malerod |author3=Steven Ray Wilson |author4=Leon Reubsaet |author5=Elsa Lundanes |author6=Tyge Greibrokk }} page 80. [[University of Oslo]], Norway</ref> In contrast, the [[Atlantic cod]] has several types of trypsins in order 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).<ref>{{cite journal |vauthors=Gudmundsdóttir A, Pálsdóttir HM |title=Atlantic cod trypsins: from basic research to practical applications |journal=Mar. Biotechnol. |volume=7 |issue=2 |pages=77–88 |year=2005 |pmid=15759084 |doi=10.1007/s10126-004-0061-9 |url=https://link.springer.com/article/10.1007%2Fs10126-004-0061-9}}</ref>

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, [[tosyl phenylalanyl chloromethyl ketone|TPCK]], which deactivates [[chymotrypsin]]. This is important because, in some applications, like [[mass spectrometry]], the specificity of cleavage is important.

Trypsin should be stored at very cold [[temperatures]] (between −20 °C and −80 °C) to prevent [[Autolysis (biology)|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 ==

The following human genes encode proteins with trypsin enzymatic activity:
{|
|- valign="top"
|{{infobox protein
|Name=[[Trypsin 1|protease, serine, 1 (trypsin 1)]]
|caption=
|image=
|width=
|HGNCid=9475
|Symbol=[[Trypsin 1|PRSS1]]
|AltSymbols=TRY1
|EntrezGene=5644
|OMIM=276000
|RefSeq=NM_002769
|UniProt=P07477
|PDB=
|ECnumber=3.4.21.4
|Chromosome=7
|Arm=q
|Band=32
|LocusSupplementaryData=-qter
}}
|{{infobox protein
|Name=[[PRSS2|protease, serine, 2 (trypsin 2)]]
|caption=
|image=
|width=
|HGNCid=9483
|Symbol=[[PRSS2]]
|AltSymbols= TRYP2
|EntrezGene=5645
|OMIM=601564
|RefSeq=NM_002770
|UniProt=P07478
|PDB=
|ECnumber=3.4.21.4
|Chromosome=7
|Arm=q
|Band=35
|LocusSupplementaryData=
}}
|{{infobox protein
|Name=[[PRSS3|protease, serine, 3 (mesotrypsin)]]
|caption=
|image=
|width=
|HGNCid=9486
|Symbol=[[PRSS3]]
|AltSymbols=PRSS4
|EntrezGene=5646
|OMIM= 613578
|RefSeq=NM_002771
|UniProt=P35030
|PDB=
|ECnumber=3.4.21.4
|Chromosome=9
|Arm=p
|Band=13
|LocusSupplementaryData=
}}
|}
Other [[isoform]]s 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]]. This disorder involves intestinal obstruction ([[ileus]]) due to overly thick [[meconium]], which is normally broken down by trypsin and other proteases, then passed in feces.<ref name="pmid11729110">{{cite journal |vauthors=Noone PG, Zhou Z, Silverman LM, Jowell PS, Knowles MR, Cohn JA | title = Cystic fibrosis gene mutations and pancreatitis risk: relation to epithelial ion transport and trypsin inhibitor gene mutations | journal = Gastroenterology | volume = 121 | issue = 6 | pages = 1310–9 |date=December 2001 | pmid = 11729110 | doi = 10.1053/gast.2001.29673| url = http://linkinghub.elsevier.com/retrieve/pii/S001650850176831X }}</ref>

==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 re-suspend cells adherent to the cell culture dish wall during the process of harvesting cells.<ref>{{cite web|url=http://www.stemcell.com/en/Products/All-Products/TrypsinEDTA-025.aspx|title=Trypsin-EDTA (0.25%) |publisher=Stem Cell Technologies |date= |accessdate=2012-02-23}}</ref> Some cell types have a tendency to "stick" - or adhere - to the sides and bottom of a dish when cultivated ''[[in vitro]]''. Trypsin is used to cleave proteins bonding the cultured cells to the dish, so that the cells can be suspended in fresh solution and transferred to fresh dishes.

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 will cause the milk to become [[translucent]]. The rate of reaction can be measured by using the amount of time it takes 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 Arg or Lys residue.

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

{{anchor|ColdZyme}}Atlantic cod trypsin is marketed under the trade name ColdZyme for prevention of [[common cold]] by the Enzymatica company, the same company that also made the underlying study wherein people administering Atlantic cod trypsin by [[oral spray]] on a daily basis were infected to a lesser degree if inoculated with [[rhinovirus]].<ref>{{cite web|url=http://www.enzymatica.com/research-development/clinical-studies|title=Clinical study on the common cold|publisher=Enzymatica|date=2014}}</ref>

=== In food ===
Commercial protease preparations usually consist of a mixture of various protease enzymes that often includes trypsin. These preparations are widely utilized in food processing:<ref name="urlProtease - GMO Database">{{cite web | url = http://www.gmo-compass.org/eng/database/enzymes/94.protease.html | title = Protease - GMO Database | date = 2010-07-10 | work = GMO Compass | publisher = European Union | accessdate = 2012-01-01 }}</ref>
* as a baking enzyme to improve the workability of dough;
* in the extraction of seasonings and flavourings from vegetable or animal proteins and in the manufacture of sauces;
* to control aroma formation in cheese and milk products;
* to improve the texture of fish products;
* to tenderize meat;
* during cold stabilization of beer;
* in the production of [[hypoallergenic]] food where proteases break down specific [[allergen]]ic proteins into nonallergenic peptides. For example, proteases are used to produce hypoallergenic baby food from cow’s milk thereby diminishing the risk of babies developing [[milk allergy|milk allergies]].

==Trypsin inhibitor==
{{main|Trypsin inhibitor}}
In order 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 [[Alpha 1-antitrypsin|α1-antitrypsin]] in the serum are present as part of the defense against its inappropriate activation. Any trypsin prematurely formed from the inactive trypsinogen would be bound by the inhibitor. The protein-protein interaction between trypsin and its inhibitors is one of the tightest found, and trypsin is bound by some of its pancreatic inhibitors essentially irreversibly.<ref>{{cite book |author=Voet & Voet |title=Biochemistry |pages=396–400|edition=2nd |year=1995|publisher=John Wiley & Sons |isbn=0-471-58651-X }}</ref> 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.<ref>{{cite journal |author1=N. Levilliers |author2=M. Péron |author3=B. Arrio |author4=J. Pudles |title=On the mechanism of action of proteolyticinhibitors: IV. Effect of 8murea on the stability of trypsin in trypsin-lnhibitor complexes |journal=Archives of Biochemistry and Biophysics |volume=140|issue=2|pages=474–483|pmid=5528741 |date=October 1970|doi=10.1016/0003-9861(70)90091-3}}</ref>

==See also==
*[[Trypsinization]]
*[[PA clan]] of proteases

== References ==
{{Reflist}}

==External links==
* The [[MEROPS]] online database for peptidases and their inhibitors: Trypsin 1 [http://merops.sanger.ac.uk/cgi-bin/merops.cgi?id=S01.151 S01.151], Trypsin 2 [http://merops.sanger.ac.uk/cgi-bin/merops.cgi?id=S01.258 S01.258], Trypsin 3 [http://merops.sanger.ac.uk/cgi-bin/merops.cgi?id=S01.174 S01.174]
* [http://www.sigmaaldrich.com/catalog/search/TablePage/15846780 Trypsin Inhibitors] and [http://www.sigmaaldrich.com/Area_of_Interest/Biochemicals/Enzyme_Explorer/Analytical_Enzymes/Trypsin.html Trypsin Assay Method] at [[Sigma-Aldrich]]
* {{MeshName|Trypsin}}

{{Serine endopeptidases}}
{{Enzymes}}
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[[Category:EC 3.4.21]]
[[Category:Peptidase]]

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Trypsin