Trypsin 30652 225561584 2008-07-14T09:18:16Z 59.90.235.17 /* Chemistry and function */ {{protein |Name=[[Trypsin 1|protease, serine, 1 (trypsin 1)]] |caption=[[X-ray crystallography|Crystal structure]] of Trypsin |image=1UTN.png |width= |HGNCid=9475 |Symbol=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 }} {{protein |Name=protease, serine, 2 (trypsin 2) |caption= |image= |width= |HGNCid=9483 |Symbol=PRSS2 |AltSymbols= |EntrezGene=5645 |OMIM=601564 |RefSeq=NM_002770 |UniProt=P07478 |PDB= |ECnumber= |Chromosome=7 |Arm=q |Band=35 |LocusSupplementaryData= }} {{protein |Name=protease, serine, 3 (mesotrypsin) |caption= |image= |width= |HGNCid=9486 |Symbol=PRSS3 |AltSymbols=PRSS4 |EntrezGene=5646 |OMIM= |RefSeq=NM_002771 |UniProt=P35030 |PDB= |ECnumber=3.4.21.4 |Chromosome=9 |Arm=p |Band=13 |LocusSupplementaryData= }} '''Trypsin''' ({{EC number|3.4.21.4}}) is a [[serine protease]] found in the [[digestive system]], where it breaks down [[protein]]s. Trypsin predominantly cleaves peptide chains at the carboxyl side of the amino acids lysine and arginine, except when either is followed by proline. It is used for numerous [[biotechnological]] processes. The process is commonly referred to as trypsin [[proteolysis]] or trypsinisation. ==Chemistry and function== Trypsin is secreted into the [[duodenum]], where it acts to [[hydrolyse]] peptides into its smaller building blocks, namely amino acids (these peptides are the result of the enzyme pepsin breaking down the proteins in the stomach). This is necessary for the uptake of protein in the food as though peptides are smaller than proteins, they are still too big to be absorbed though the lineing of the ileum. Trypsin [[catalysis|catalyses]] the hydrolysis of peptide bonds. The enzymatic mechanism is like all other serine proteases: A [[catalytic triad]] serves to make the [[active site]] [[serine]] nucleophilic. This is achieved by modifying the electrostatic environment of the serine. The enzymatic reaction that trypsins catalyze is [[thermodynamics|thermodynamically]] favorable but requires significant [[activation energy]] (it is "[[enzyme kinetics|kinetically]] unfavorable"). Trypsins have an optimal operating [[pH]] of about 8 and optimal operating temperature of about 37°C.{{ref_label|1|1|a}} The [[aspartate]] residue (Asp 189) located in the catalytic pocket (S1) of trypsins 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 followed by [[proline]].{{ref_label|1|1|a}} Trypsins are considered [[endopeptidase]]s, i.e., the cleavage occurs within the [[polypeptide]] chain rather than at the terminal amino acids located at the ends of [[peptide|polypeptides]]. Trypsin is produced in the [[pancreas]] in the form of inactive [[zymogen]], [[trypsinogen]]. It is then secreted into the [[small intestine]], where the enzyme [[enteropeptidase]] activates it into trypsin by proteolytic cleavage. The resulting trypsins themselves activate more trypsinogens ([[autocatalysis]]), so only a small amount of enteropeptidase is necessary to start the reaction. This activation mechanism is common for most serine proteases, and serves to prevent autodigestion of the pancreas. The activity of trypsins is not affected by the [[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. ==Involvement in disease== One consequence of inheriting the autosomal recessive disease [[cystic fibrosis]] is a deficiency 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 trypsins and other proteases, then passed in feces. ==Storage== Trypsins should be stored at very cold [[temperatures]] (between −20°C and −80°C) to prevent autolysis (self-cleavage). [[Autolysis]] may also be prevented by storage of trypsins at pH 3 or by using trypsin modified by e.g. reductive methylation. When the pH is adjusted back to pH 8 activity returns. ==Applications== Trypsin is available in high quantities in pancreases, and can be purified rather easily. Hence it has been used widely in various biotechnological processes. In a [[tissue culture]] lab, trypsins are used to re-suspend cells adherent to the cell culture dish wall during the process of harvesting cells. Trypsin can also be used to dissociate dissected cells (for example, prior to cell fixing and sorting). Trypsins can be used to breakdown 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. Trypsin is used in baby food to pre-digest it. It can break down the protein molecules which helps the baby to digest it as its stomach is not strong enough to digest bigger protein molecules. ==See also== * [[Trypsin inhibitor]] ==References== # {{note_label|1|1|a}} Promega [http://www.promega.com/tbs/9piv511/9piv511.pdf PDF - 58kB] {{Enzyme references|EC_number=3.4.21.4|IUBMB_EC_number=3/4/21/4}} ==External links== * [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}} {{Enzyme links|EC_number=3.4.21.4|IUBMB_EC_number=3/4/21/4}} {{Serine endopeptidases}} [[Category:EC 3.4.21]] [[ca:Tripsina]] [[cy:Trypsin]] [[da:Trypsin]] [[de:Trypsin]] [[es:Tripsina]] [[eo:Tripsino]] [[fr:Trypsine]] [[is:Trypsín]] [[it:Tripsina]] [[he:טריפסין]] [[nl:Trypsine]] [[ja:トリプシン]] [[no:Trypsin]] [[oc:Tripsina]] [[pl:Trypsyna]] [[pt:Tripsina]] [[fi:Trypsiini]] [[sv:Trypsin]] [[tr:Tripsin]] [[zh:胰蛋白酶]]