Trypsin-1, also known as cationic trypsinogen, is a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, respo ...
that in humans is encoded by the ''PRSS1''
gene
In biology, the word gene (from , ; "...Wilhelm Johannsen coined the word gene to describe the Mendelian units of heredity..." meaning ''generation'' or ''birth'' or ''gender'') can have several different meanings. The Mendelian gene is a ba ...
. Trypsin-1 is the main
isoform
A protein isoform, or "protein variant", is a member of a set of highly similar proteins that originate from a single gene or gene family and are the result of genetic differences. While many perform the same or similar biological roles, some isof ...
of
trypsinogen Trypsinogen () is the precursor form (or zymogen) of trypsin, a digestive enzyme. It is produced by the pancreas and found in pancreatic juice, along with amylase, lipase, and chymotrypsinogen. It is cleaved to its active form, trypsin, by enterop ...
secreted by pancreas, the others are
trypsin-2 (anionic trypsinogen), and
trypsin-3 (meso-trypsinogen).
Function
This gene encodes a trypsinogen, which is a member of the
trypsin
Trypsin is an enzyme in the first section of the small intestine that starts the digestion of protein molecules by cutting these long chains of amino acids into smaller pieces. It is a serine protease from the PA clan superfamily, found in the dig ...
family of
serine protease
Serine proteases (or serine endopeptidases) are enzymes that cleave peptide bonds in proteins. Serine serves as the nucleophilic amino acid at the (enzyme's) active site.
They are found ubiquitously in both eukaryotes and prokaryotes. ...
s. This enzyme is secreted by the pancreas and cleaved to its active form in the small intestine. It is active on peptide linkages involving the
carboxyl group
In organic chemistry, a carboxylic acid is an organic acid that contains a carboxyl group () attached to an R-group. The general formula of a carboxylic acid is or , with R referring to the alkyl, alkenyl, aryl, or other group. Carboxylic ...
of
lysine
Lysine (symbol Lys or K) is an α-amino acid that is a precursor to many proteins. It contains an α-amino group (which is in the protonated form under biological conditions), an α-carboxylic acid group (which is in the deprotonated −C ...
or
arginine
Arginine is the amino acid with the formula (H2N)(HN)CN(H)(CH2)3CH(NH2)CO2H. The molecule features a guanidino group appended to a standard amino acid framework. At physiological pH, the carboxylic acid is deprotonated (−CO2−) and both the am ...
. Mutations in this gene are associated with hereditary
pancreatitis
Pancreatitis is a condition characterized by inflammation of the pancreas. The pancreas is a large organ behind the stomach that produces digestive enzymes and a number of hormones. There are two main types: acute pancreatitis, and chronic pancr ...
. This gene and several other trypsinogen genes are localized to the T cell receptor beta locus on chromosome 7.
Clinical significance
Its malfunction acts in an autosomal dominant manner to cause pancreatitis. Many mutations that can lead to pancreatitis have been found. An example is a mutation at Arg 117. Arg 117 is a trypsin-sensitive site which can be cleaved by another trypsin and becomes inactivated. This site may be a fail-safe mechanism by which trypsin, when activated within the pancreas, may become inactivated. Mutation at this cleavage site would result in a loss of control and permit autodigestion, causing pancreatitis.
See also
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Trypsin
Trypsin is an enzyme in the first section of the small intestine that starts the digestion of protein molecules by cutting these long chains of amino acids into smaller pieces. It is a serine protease from the PA clan superfamily, found in the dig ...
References
Further reading
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External links
GeneReviews/NCBI/NIH/UW entry on PRSS1-Related Hereditary Pancreatitis*
EC 3.4.21
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