Trypsin 1

Trypsin-1, also known as cationic trypsinogen, is a is_associated_with::protein that in humans is encoded by the PRSS1 is_associated_with::gene. Trypsin-1 is the main is_associated_with::isoform of is_associated_with::trypsinogen 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 is_associated_with::trypsin family of is_associated_with::serine proteases. 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 is_associated_with::carboxyl group of is_associated_with::lysine or is_associated_with::arginine. Mutations in this gene are associated with hereditary is_associated_with::pancreatitis. 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.