Trypsin is a member of the serine protease family. It cleaves proteins and peptides into smaller pieces by hydrolyzing peptide bonds at the carboxyl side of lysine and arginine residues. Trypsin is produced by the pancreas as an inactive trypsinogen and is then secreted into the small intestine, where it is cleaved by enteropeptidase and becomes activated. Trypsin activity aberration is implicated in gastrointestinal disorders such as pancreatitis and intestinal mucosal pathology. ScienCell's Colorimetric Trypsin Activity Assay Kit (TRYP) offers a rapid and sensitive way to determine the trypsin activity in mammalian cell/tissue lysates, serum, plasma and other biological fluid samples. Briefly, trypsin cleaves the substrate and releases p-nitroanilide (pNA), a chromophore that can be measured at 405 nm using a spectrophotometer. Chymotrypsin, another structurally similar serine protease, does not interfere with this assay because it does not cleave the trypsin substrate to release pNA.