Trypsin is a 24 kDa enzyme of the serine proteinase family. It is produced in the pancreas as an inactive precursor, trypsinogen, but the active enzyme is located in the gastrointestinal tract where it degrades proteins to large peptides. Trypsin prefers lysine and arginine residues. One of the substrates for trypsin is chymotrypsinogen which is cleaved to produce active chymotrypsin. High levels of immunoreactive trypsin in the bloodstream can indicate pancreatic malfunction and this indicator is used to screene for and diagnose Cystic Fibrosis. This antibody is specific for human trypsin, trypsinogen and trypsin in comple, Xenopus/Amphibian, with alpha-1-antitrypsin and reacts weakly with bovine trypsin.