This old version of Proteopedia is provided for student assignments while the new version is undergoing repairs. Content and edits done in this old version of Proteopedia after March 1, 2026 will eventually be lost when it is retired in about June of 2026.
Apply for new accounts at the new Proteopedia. Your logins will work in both the old and new versions.
Sandbox 46
From Proteopedia
|
Contents |
Trypsin
Trypsin, a member of the serine protease family, is produced in the pancreas and found in the digestive tracks of vertebrates. To avoid pancreatic self-degradation, trypsin is synthesized as trypsinogen, a zymogen. Cleavage by enteropeptidase allows tryspin to enter its active form. As a serine protease, trypsin contains a serine residue in its active site.
Structure
The trypsin structure displayed is a mutant form isolated from a bovine pancreas. It contains 58 amino acid residues as well as an altered binding loop. To follow the primary structure (amino acid sequence) of Trypsin, click Begin at the N-terminus (blue) and move toward the C-terminus (red).
The of Trypsin consists of two alpha helices (light green) and two beta sheets (peach). Hydrophobic interactions - mainly the hydrophobic collapse - significantly contribute to both secondary and tertiary structure. This shows that the majority of the residues are non-polar/hydrophobic (maroon). These residues tend to congregate on the interior of the structure while polar/hydrophilic residues (blue) remain on the exterior. This orientation allows polar molecules to maximize interaction with water and other polar molecules while non-polar molecules minimize such interactions. Adding water molecules to the model, the interactions can be seen.
Stability
The yellow and red molecules represent SO4 (2-) moieties which are not part of the traditional trypsin structure; they were added during crystallization to freeze Trypsin in a specific conformation. Fix THIS. they bind at active site
Function
The reaction catalysed by Enteropeptidase:
trypsinogen → trypsin + hexapeptide
Val--(Asp)4--Lys--Ile--Val~ (trypsinogen) → Val--(Asp)4--Lys (hexapeptide) + Ile--Val~ (trypsin)
Enteropeptidase cleaves after Lysine if the Lys is preceded by four Asp and not followed by a Pro. Source ^ "Enterokinase, light chain (P8070), Proteases, NEB". http://www.neb.com/nebecomm/products/productP8070.asp. Retrieved 2007-10-04.
Shared active site
