Trypsin

• OMIM: 276000
• UniProt: P07477

Human Trypsin is a mixture of three digestive enzymes that degrade proteins in the small intestine and are among the peptidases: Trypsin -1 (cationic trypsin, two-thirds), trypsin -2 (anionic trypsin, about one third) and trypsin -4 ( mesotrypsin, a few percent ). Many similar enzymes in mammals, insects, fish and mushrooms also bear the name of trypsin.

Lack of trypsin -1 in humans leads to malnutrition due to protein deficiency. Cause may be a mutation in the gene try1. Another consequence of such a mutation is hereditary pancreatitis, the body's own trypsin -1 can not be broken down and digested the pancreas. Mutation on the gene for trypsin -2 may contribute to chronic pancreatitis.

Biosynthesis

The proteases trypsin, chymotrypsin and carboxypeptidases are used as inactive zymogen precursors, secreted by the pancreas. The intestine enteropeptidase enzyme bound to the intestinal epithelium controls the conversion of the precursor trypsinogen to trypsin. Trypsin activates itself (positive feedback ) and converts chymotrypsinogen, procarboxypeptidase and proelastase as well as other inactive enzymes in their active forms ( chymotrypsin, elastase and carboxypeptidase ) to.

Biological Function

Trypsin is one of the endopeptidases cleave proteins at specific locations. Trypsin is a serine protease. Trypsin selectively cleaves peptide bonds after intestinal region after the basic amino acids lysine, arginine, and also by a modified cysteine. Proteinases are not specialized in certain proteins, but to specific amino acid sequences ( structural features ) within proteins; This is important for the digestive process, as would otherwise be required in a particular enzyme in the small intestine for each occurring protein.

Endopeptidases are important substances in the chemical-analytical protein sequencing. The cleaved ( denatured ) proteins are readily hydrolyzed and bind water molecules per se.

A similar function and effect, the released of the gastric wall pepsin.

Use

Trypsin has a pH optimum of 7-8, thus operates in basic conditions ( such as they actually exist in the small intestine ) the most effective.

In cell culture laboratory trypsin is used to solve adherent cells from the bottom of the culture dishes or to separate cells by. As long as the cells are treated with trypsin for too long, they are not damaged and only the extracellular proteins are cleaved.

In proteomics is the protease trypsin most widely used to produce peptides for mass spectrometric analysis, for example, during in-gel digestion.

For chromosome analysis in the form of a karyogram the chromosomes are treated with trypsin and then stained with Giemsa in the GTG - banding technique.

Detection reaction

The activity of trypsin may be detected by N-benzoyl- D, L- arginine -p- nitroaniline ( BAPNA ). Thereby BAPNA is cleaved by the trypsin at the arginine and there is p-nitroaniline. The concentration of p-nitroaniline may be detected by spectroscopy at a wavelength of 405 nm.