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Trypsin

Trypsin is a serine protease that found in the digestive system of many vertebrates, where it hydrolyses proteins[1].

Trypsin is produced in the pancreas as the inactive zymogen protease called trypsinogen. trypsinogen secreted into the small intestine where it activates trypsinogen into trypsin by the enzyme Antrookinaz using proteolytic decomposition. Trypsin Break peptide chains at the carboxyl side of the amino acids lysine or arginine, except when it is followed by proline. .

Function

Trypsin catalyzes the hydrolysis of peptide bonds and cutting proteins into smaller peptides in the duodenum.

Structure and Mechanism

Trypsin is a medium size globular protein that contains either alpha helix and beta sheets. The enzymatic mechanism of Trypsin is similar to the other serine proteases. These enzymes contain a catalytic triad consisting of histidine-57, aspartate-102, and serine-195, These three residues makes the active site serine nucleophilic [2].

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 located in the catalytic pocket of trypsin is responsible for attracting and stabilizing positively charged lysine or arginine, and as a result responsible for the specificity of the enzyme [3].


Structural highlights

There are different ways to present the protein structure :balls and stick, surface and Backbone. Another way to view the protein is Rainbow that show the protein from the N (blue) to C terminal (green).


Bovine trypsine complex with inhibitor and Ca+2 ion (green) (PDB code 1y3v)

Drag the structure with the mouse to rotate

References

  1. Rawlings ND, Barrett AJ. Families of serine peptidases. Methods Enzymol. 1994;244:19-61. doi: 10.1016/0076-6879(94)44004-2. PMID:7845208 doi:http://dx.doi.org/10.1016/0076-6879(94)44004-2
  2. Polgar L. The catalytic triad of serine peptidases. Cell Mol Life Sci. 2005 Oct;62(19-20):2161-72. PMID:16003488 doi:http://dx.doi.org/10.1007/s00018-005-5160-x
  3. Rodriguez J, Gupta N, Smith RD, Pevzner PA. Does trypsin cut before proline? J Proteome Res. 2008 Jan;7(1):300-5. Epub 2007 Dec 8. PMID:18067249 doi:http://dx.doi.org/10.1021/pr0705035

Proteopedia Page Contributors and Editors (what is this?)

Lotem Haleva, Michal Harel

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