Trypsin

The enzyme trypsin cleaves proteins at the carboxyl side (or "C-terminus") of the basic amino acids lysine and arginine. Trypsin is considered an endopeptidase, i.e. cleavage occurs within the polypeptide chain rather than at the terminal amino acids located at the ends of polypeptides. Mechanistically, trypsin catalyzes the hydrolysis of polypeptides, a thermodynamically favorable reaction that requires significant activation energy (that is to say, the reaction is kinetically unfavorable). 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. The optimum pH for trypsin is 8.

Related Topics:
Carboxyl - Lysine - Arginine - Hydrolysis - Aspartate

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Trypsin is produced in the pancreas in the form of trypsinogen, and is then transported to the small intestine, where begins the digestion of proteins to polypeptides and amino acids. Trypsin is an autocatalytic enzyme; that is, trypsin catalyzes the conversion of trypsinogen to trypsin. A small amount of another enzyme, enterokinase, is required to catalyze the initial reaction of trypsinogen to trypsin.

Related Topics:
Pancreas - Trypsinogen - Small intestine - Proteins - Polypeptide - Amino acids - Autocatalytic - Enzyme - Catalyzes - Enterokinase

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Trypsin is often modified by TPCK, tosyl phenylalanyl chloromethyl Ketone, which will inactivate chymotrypsin. This is important because in some applications, like mass spectrometry, the specificity of cleavage is important.

Related Topics:
TPCK - Mass spectrometry

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Trypsin should be stored at very cold temperatures (between −20 and −5-6C) to prevent denaturation.

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In a tissue culture lab, trypsin is used to re-suspend cells adherent to the petri dish wall during the process of harvesting cells.

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